Archive of Our Own ^beta

Leo felt something hit his chest, getting thrown back before a cloud of pink smoke surrounded him. Coating his lungs, making him cough. Somewhere in the distance his brothers screamed his name but he was too focused with the powdery gas filling his lungs to really pay that much attention. 

Coughing to try and get rid of it but only succeeding in getting more of it caught in his throat. 

Passing out for just a moment. 

Coming to with all the smoke finally gone and Donnie in front of him. Looking down with a very worried and confused expression, something not often seen in Donnie’s face. 

“What?” Leo asked, too tired for his normal snark. Voice more higher pitched then normal. Passing out again before Donnie could answer him. 

“Well you seem to be fine,” Donnie said, putting his hands on his hips as he stared down at Leo, “Hopefully your blood tests will show us more about whatever the hell happened to you.”

“It’s pretty obvious what happened to me Dee,” Leo whined, pouting, “Our lovely villain threw some magicy things at me that turned me fucking 13 again.” As if to show off that, his voice squeaked right at the end. Only making his pout deepen, especially as Donnie had to hold himself from laughing. 

“Being serious,” Donnie said, coughing as his face turned serious. Well for him at least, “the blood tests I’m hoping will more of tell us that whatever this is, isn’t going to slowly turn you into a baby and kill you. I’m thinking you’re just going to be a young teen for a bit and then hopefully turn back to your normal age.”

Leo hadn’t actually been out of his teens for long but he was not looking forward to returning to them. Especially this close to having turned 21, he liked drinking and there was no way anyone would serve him alcohol looking like he did. 

He had caught himself in a mirror since waking back up and before Donnie had rushed in to give him the low down of the fight, along with poking and prodding at every inch of him. Much smaller in multiple ways, clearly at least 13 now. More chubby cheeked and less muscle than he had in his older body. Although it wasn’t even 10 years younger. His shorts didn’t fit him anymore, Mikey had run to his room to grab him a pair that actually fit. An old pair that had apparently been in the way back of his closet. 

But there was one thing specifically he was worried about. Opening his mouth to ask his brother about it before his two brothers had entered. Both worried out of their mind. When Mikey had run out to grab him a pair of shorts, Leo had still been passed out. And Raph had apparently been too nervous to come and see him when he wasn’t awake. 

Both of them were so focused on fawning over if Leo was fine or not, he didn’t get to ask Donnie his question. 

“Hey,” Leo said, finally looking down at Donnie for the first time that day. They were normally the same height so it was weird, and annoying, to have to look up at his twin all day. He tried to make his voice deep and seductive but with his younger voice, it sure didn’t sound that way. At least Donnie didn’t laugh at him this time. 

Instead he looked up at him, one sharpie eyebrow raised but he didn’t move either. Which he could have easy done now. Leo was so much smaller than he was. He could easily push him off and get off the bed where Leo had pushed him. He didn’t however. 

“What do you want Leo?” He sighed instead. Still not moving. Which Leo counted as a win. 

As such, he smirked down at his now big brother, waggling his brows. Even if it wasn’t as effective without eyebrows. Maybe he should ask Donnie to draw ones on his mask. But he quickly banished that line of thinking. Instead focusing on what he really wanted. 

“You know what me being a young teen again means?” Leo asked, staring down at his brother with what he hoped with seduction. Donnie didn’t respond, continuing to stare up at Leo with no emotion on his face, “Means you can take my first time aga—”

“Yeah that is not happening,” Donnie said, finally pushing Leo off. Just as easy as he thought he would be able to. Leaving Leo to sit on the floor, pouting up at Donnie, “I’m going to go back to my lab and do some more tests. If you’re still here when I come back, I’m sleeping on the couch.”

Donnie didn’t let him say anything more before he was walking out the door. Leaving Leo on the floor, horny and upset. 

Even without newly raging teenage hormones, Leo was very horny. Very rarely was Donnie the one to initiate sex between the two of them and when he did there had only been a few times that Leo had said no. He could count them on his hands. 

But along with that, Donnie was a massive creep. 

Leo had thought he would jump at the opportunity to take Leo’s virginity yet again. Although they had both been older than Leo’s body was now when they had fucked the first time. 

Although thinking back, it had taken Donnie quite a bit of convincing to fuck him that first time and then to continue their relationship. But now that they were together Leo knew his boyfriend/brother was a freaky creep. Even this he was sure Donnie would be into. Had seen the weird hunger in his eyes looking down at pictures of a young Leo. 

And there was just no way Leo was going to survive however long without sex. Especially with all those fresh puberty hormones. He’d been horny the first time around when he’d had evil to focus on. But now that there was a lot less to focus on, it would be ten times worse. He didn’t even want to think about what would happen if he didn’t just go back to normal. 

“Well, I got in contact with Draxum,” Donnie said the next day. Neither of them mentioning Leo having come onto him the day before. Leo was still pouting about it, “and you’ll probably be fine after a month or so. He says you can probably go about with training and what not but it might be best if you stay out of the way. We don’t want any villains taking advantage of this.” 

“First no sex and now no fighting?” Leo whined, falling back and making the wax paper under him crinkle. Not even having to see Donnie to know he was currently rolling his eyes. 

“I guess you’ll just have to find another way to blow off steam,” Donnie said, words dripping with sarcasm. 

“Ughhh,” Leo groaned, before getting back up slowly, giving Donnie his best puppy dog eyes. Not as good as Mikey’s but he hoped this was one of the times it worked, “Can’t we even just kiss?”

Donnie didn’t even look at him, continuing to look down at his tablet, “I am not falling for that Leo.”

“Fuck,” Leo said, voice more whiny than he wanted. Even more whiny than normal with his even younger voice. His voice cracking slightly at the curse. 

“Be careful,” Donnie said with a smirk, finally looking up, “Raph would scold you for that kind of language.”

Leo groaned again when his brother laughed. Raph had been babying him even more than usual. He may not look it but he was still an adult and even then his body was about 13 but Raph was treating him more like he was 3. One of the things he didn’t seem to tolerate out of Leo’s mouth was anything resembling a curse. He’d gotten scolded for the use of the word dang. 

“You’re evil you know that,” Leo said with a pout and a glare. Donnie shrugged, hot smirk still on his face. 

“Been told that for quite a few years Leo, it is not even slightly news to me.” 

For the next day, Leo spent it mostly pouting. Having to watch as his brothers went out to patrol without him. He was the leader! How the hell were they supposed to go without him?

Of course he knew his brothers could handle themselves. In fact he was the one more often getting them into trouble. He knew it was just the underlying want to get out of the damn lair. He was bored. And the fact that Donnie refused to fuck him did not help even a little bit. 

But after a proper day of pouting he got to work. He’d seduced Donnie before and he could do it again. He’d had to be the one to make the first move all those years ago and he was going to do it again. Because he couldn’t last a month or anything more than that without getting fucked by his brother. 

He took another few days to plan and more importantly to make sure that Donnie didn’t suspect anything. He spent time around his brother of course, even outside of training. But he didn’t make a single move on him knowing that would just tip Donnie off. So instead he played innocent. Sat in the corner of the lab specially reserved for him while Donnie worked, reading a comic book or playing on his phone or watching some show. Occasionally sharing with his brother something he’d seen. 

And once Donnie seemed used to it after a few days, he sprung his first trap. 

It had been a while since Leo had slept on his own before this whole thing started. Normally he was sleeping either in Donnie’s room or in the lab in the mattress he kept there for late nights. The first night he had disobeyed Donnie and stayed in his room the whole night. But like he had promised, he hadn’t come to sleep in his own bed. Although he’d just slept on the mattress in the lab. 

But since then Leo’d been sleeping in his own bed. It was lonely, lonelier the he’d thought it would be. One advantage was that his room was now close to Donnie’s. Their rooms having been moved around who knows how many times. Donnie had moved his room to be closer to the lab for ease meaning he was right next to Leo. 

“Ahhh!” Leo didn’t hold back his moans, pushing the toy further into him. His bed pressed against the wall he shared with Donnie. The rest of the family was on the other side of the lair now, not able to hear as Leo let another moan out. 

His trusty purple dildo pressing right against his prostate. Making his toes curl from the pleasure. Speeding the thrusts up as he felt himself getting closer and closer. His cock twitching against his lower plastron, cum already streaking across it. 

This would be his third orgasm of the night and he could tell it wouldn’t be his last. But no matter how many times he came, it just didn’t feel the same. 

He was so used to Donnie fucking him, even the dildo he’d gotten that was as close to his beloved soft shell didn’t feel the same. It had been too long since he’d had to jerk off instead of being fucked. That combined with the hormones of a teen again, he was slightly disappointed by every orgasm. 

“Dee!” He whined out as the toy hit right against his prostate again, cumming. But he didn’t stop for even a second. Still not touching himself outside of the toy inside him. Whining as he imagined Donnie there with him instead on the other side of this accursed wall. 

Imagined Donnie fucking his cock inside. Maybe even ripping the toy out of him before shoving his own cock inside. Now he wouldn’t under normal circumstances, let alone now, but still couldn’t help the way his cock twitched again with interest, “Please,” the word was whined and drawn out. Thoughts drifting away from the fantasy and wondering what his brother was doing just one room over. 

He had heard Donnie’s door close earlier so he knew his twin was in his room. Wondered if he was jerking off as well. Pressed against the wall to make sure he could hear as much as possible. Maybe even grabbing out the camera Leo knew he had installed in Leo, and everyone else’s, room. 

And he knew that this wouldn’t be the thing to make his brother burst into his room and fuck him into the mattress. He wished it would be, but Donnie had more resolve than that. 

No, this was just the first part to his scheme. Trying to make his brother so horny he couldn’t help but need to fuck Leo when he did even the smallest thing. Because while Donnie had told him he jerked off, it was really only when there was no other choice. 

Had groaned into Leo’s ear when they finally came back together after a long mission where they had to be separated for one reason or another. Told him that it was just never the same. That he preferred fucking Leo to his hand. That jerking off just made him want Leo more. 

But Leo also knew just knowing his brother that it’s not like celibacy would help with that either. So if Donnie jerked off to his noises or not, it would just make him more susceptible to Leo’s seduction. 

Unfortunately however, even after cumming several times, Leo was ultimately left unsatisfied. The toy slowly falling out onto the bed as Leo caught his breath. Before getting up and portaling to the bathroom where he could clean the toy and himself up. Before heading to actually sleep.

He continued to do it every night. Waiting until his brother was in his room, if he went in there, before fucking himself with the toy. And while he didn’t mention anything, neither did Donnie. Neither of them even seemed to be any different.  

But Leo could see the difference himself. Seeing the way Donnie looked at him the next day after the first time, clearly tired. Probably stayed up all night thinking about it over and over again. Diving further into his work to distract himself. The way he would clearly look at Leo’s ass when he bent over, fully at the waist every time Donnie was in the room. 

Which just gave him his next idea.

The most they wore in terms of clothes was their shorts more often than not. Just something to protect all of the important parts as that had to be the place they picked up more human genetics. But especially during training or any sort of exercise, they wore as little as possible. 

That didn’t mean that Leo didn’t own anything that could be called exercise clothes. 

He used to wear them more often meaning he had a decent amount of tight pants that hugged his ass nicely that actually fit him like he wanted. Which was perfect for his current plan. 

“I’m so glad that you decided to join me to do some yoga!” Mikey said, voice super enthusiastic. 

“It not like I’m allowed to do much else,” Leo said with a small pout. Making Mikey laugh. 

“Normally you guys don’t show up to my weekly yoga sessions,” Mikey said, moving them into another pose. It was close to a week since Leo had been Deaged and he was going insane. Sure because he was horny but he hadn’t been lying to Mikey when he’d complained about not being able to go out and do anything, “Well at least not for the actual yoga.”

Mikey always did it right in the middle of where they always trained so it was a little hard for them to never show up even if they weren’t going to participate. And very rarely did any of them for one reason. That reason being that Mikey was way more flexible than any of them and didn’t ever remember this. Meaning that it was always more painfully then they expected. Even Leo, the second most flexible of the brothers, couldn’t always keep up. 

“I wonder why,” he huffed slightly, not even because he was annoyed. Moving into what Mikey said was the Compass Pose but Leo was sure it looked nothing like that when he did it. Mikey did it perfectly however. 

“You guys just need to do it more and you’ll get better,” Mikey said with the same enthusiastic and optimistic smile he had on often. Leo highly doubted that. 

As they moved, Leo moving so his ass was perfectly seen, he could hear footsteps approach. Along with Ralph’s loud voice, “— some more training!”

“I don’t nee—” Donnie started but seemed to be cut off by something. 

And this was the other reason Leo had decided to join his younger brother for yoga. Had planted the idea in Ralph’s head that Donnie wasn’t getting enough training in, something about being cooped up in his lab. Then knowing that Raph would drag Donnie out of his lab with that. And that he usually came to work out while Mikey was doing his yoga. He said it kept him working out despite the fact that he did it every day but before Mikey had taken up his weekly yoga, Raph did his working out early in the morning. Then suddenly he was interested in working out later in the day. Leo had his suspicions but it wasn’t important right now. 

What was important was the fact that Leo had chosen just the right pair of pants to make sure that his ass was shown off perfectly. And then chose a great place in front of the door to make sure that if Donnie walked in, he would see Leo’s ass looking fantastic. 

But he pretended like he didn’t even know Donnie was there. Continuing to move as Mikey did. 

However Mikey seemed to notice. Eyes drifting from Donnie to Leo back to Donnie again before smirking over at Leo. But he didn’t mention anything, continuing like they had been.

The brief cutting off of himself was quickly taken advantage of, Donnie being dragged off to the weights. Leo watched the two of them through the mirror that they’d recently put in. Watching as Donnie clearly tried to get Raph to go back on this idea that he needed to work out more. Raph didn’t budge however, instead just packing some weights onto the bar no matter if Donnie wanted it or not. 

All through the conversation, Donnie kept sneaking glances at Leo’s ass. Seemingly forgetting that Leo could clearly see where his eyes were looking whenever he wanted to. Not that he was going to mention it of course. 

Instead as he moved into yet another pose that put his ass high in the air, he swayed slightly. Watching Donnie’s eyes bulge out of his head before quickly looking away. Leo having to hold back a laugh. 

It seemed Donnie hadn’t been able to talk his way out of lifting. Instead sighing, giving one last glance towards Leo’s ass before laying down against the bench. Leo wished him luck internally. 

Raph always overestimated what others could lift, given how much he himself could. As such most of them could barely lift it once let alone do multiple reps. And Donnie did not do much training and when he did, it wasn’t with weights. Leo highly doubted he could lift it. 

Watching from the mirror as his brother grabbed the bar and took a deep breath. Mikey snapped in front of his face, reminding him to focus on the poses. Which only lasted for a moment before Leo’s eyes were once again drawn to the mirror where Donnie was once again trying to get out of lifting it. Taking another deep breath before lifting the weights up. 

“You had to have put less on than you normally do,” Leo said, eyes wide. Breaking the illusion. Dropping the yoga pose he had been in and turning an accusatory finger towards Raph. 

Donnie put down the weight, which he had lifted rather easily, as Raph turned towards Leo, brow raised. Head tilted to the side and about to ask more. 

“I may not do much training like the rest of you,” Donnie said as he sat up, “but I can’t call Raph over to lift everything for me Leo.” 

Leo gaped at Donnie, seeing as he had walked closer just how much Raph had packed on there. More than Leo had ever been able to lift that was for sure. Looking between the weights and Donnie before giving a loud huff and stomping out of the room. 

He had gotten what he had wanted after all. Had shown his ass off in his tight pants. Which Donnie had gotten quite a bit of an eye full of. 

And if when he was shoving his dildo into himself that night, moaning just as loudly as before, he was thinking about Donnie lifting him up at his normal height and weight, who had to know?

(Yes he did think briefly about Donnie tossing him around when he was this age. But it was more impressive when Leo was taller and had more muscle and weight to him and as such much hotter.)

It was about a week until it had been a month and Leo felt like he was going to explode with how horny he was. It didn’t matter how much he jerked off or fucked himself, it just made the desperation worse. Made him want his brother to actually fuck him more.

And he knew that he didn’t, hopefully, have much longer until his body was back to normal but it was torture nevertheless. The only thing he was happy about was that it seemed like Donnie was being just as affected by it. Avoiding Leo as much as he could. Locking himself away in the lab at any moment when they weren’t doing anything else. And while it meant that Leo didn’t get to see him much, but it did mean at the very least he could see that this was all affecting him just as much as this was affecting Leo so at least he could use that to make him feel a little bit better.

Deciding that he was done with all of this, he brought out what he hoped would be the last thing he would have to do. Hoping that this would be what would finally throw Donnie over the edge.

Once the lair was mostly empty, it only being him and Donnie, he grabbed out his favorite dildo from out of his nice hiding place for it along with the bottle of lube he kept near it. Most often when he was doing this, he laid down in his bed but today he did something different. Instead sticking the suction cup bottom to the floor in the middle of his room. 

But that was just to make sure that he was ready. Kneeling near it so that it would be right in the background before he grabbed the bottle of lube. Before all of this, it had been new, not able to be used before he got magically transformed. Half of it was gone now. After squirting some into his hand, he moaned as he took himself in his hand, not having to worry about his pants which he had already thrown off, giving a few small pumps. Hands enveloping his entire dick. He didn’t pay too much attention there, hand quickly moving further down. 

Gasping as he pressed inside his hole. Not being gentle with himself, instantly searching out the spot that would make him feel best. Moaning loudly as he quickly found it, pressing the pad of his finger against it. Only barely able to reach it, whining as he thought of how easily Donnie’s hands, now even bigger in comparison to his small body, would be able to find the spot. Go beyond it and fuck far into his guts.

As his whines and moans grew louder, he fumbled around for his phone which he had placed near him. But with the pleasure, it was a little hard to find it on the ground. Hands bumping into it eventually, not stopping his finger inside himself and instead adding another as he tried to open up his camera.

Not holding back as he pointed it down towards where he was fingering himself before pressing the red recording button. Letting out a loud moan as he hit right against his prostate, whining out, “Donnie,” before stopping the video. Watching it panting as he slowed his fingers down. Could feel himself getting closer and not wanting to cum off camera. After watching it a few times, he figured it was good, not too shaky which he had been worried about and seemed to get everything in frame. Showing off where his fingers were fucking inside himself along with his lower plastron where his dick laid against it, leaking out. And the dildo in the background, waiting for him to use it.

He triple checked he had the right contact before sending it to Donnie. He did not want to be sending his dad videos of him jerking off. Saying under the video, “No one else is home”.

Before putting the phone down and leaning on the very hand that had been holding his phone, getting a whole new angle to finger fuck himself. Letting out more moans of his brother’s name. Tempted to stick his whole hand inside of himself before getting himself together enough. This wasn’t the end of his plans after all. But he couldn’t help himself a little bit at least.

Picking back up his phone and turning on the camera as he continued to assault the spot that was making him feel so good. Moaning and begging Donnie as he let himself get close, not taking long before he was falling over the edge. Giving one last small whine of, “Please Donnie,” before he turned the video off. Letting himself rest for a moment as he sent off the next video.

Not taking long before he was ready to go again, already hornier than before. Grabbing the lube once again and this time spreading some onto the dildo. It looked so much bigger now even though he knew that it was just himself that was smaller not the other way around. His hand just barely wrapped around the whole thing and at the base, there was a small bit of a gap between his fingers.

He didn’t waste much time, knowing he should have taken longer to coat the whole thing but he couldn’t. Couldn’t wait the few minutes to do so. Facing away from the door as he picked himself up, pressing the silicone head against his hole, wishing that Donnie was here not for the first time over this month.

Before realizing this would be a great moment to film. Grabbing his phone and setting it up in front of himself. Thankful that it only took a minute to actually get set up. It showing up to the top of his chest and down to the floor. Turning on the video before he was pressing himself down with a moan. Watching himself carefully in the camera as he pressed down on the dildo.

It felt so much different than it had the last few weeks. The angle so much different and rubbing against his insides so intensely. It somehow felt even bigger in this position. So much thicker.

As he pressed down farther, he could see more of him coming into frame. Watched his thighs as he moved down, glad that he was at least flexible enough that the way he was pressing himself down to the ground didn’t hurt even if he was sure it would hurt later. He couldn’t bring himself to care too much right now.

Instead continuing to press himself farther down, hand coming down as he got closer to the bottom. Pressed flat against the floor in front of him to hold himself up, give himself better balance. Moans spilling out of him easily, Leo not even able to stop it. 

Looking into the camera, watching as he finally pressed the last inch inside of himself. Whining at the sight, “Fuck Donnie,” his eyes shut, mouth wide open, “I wish this was you so badly.”

He was rather quick to get used to the sensation, bringing himself up just a little bit before slamming back down with a loud moan. Readjusting himself to be leaning back instead of forward as he fucked himself on the dick, moaning out Donnie's name rather loudly. Begging his brother to come and fuck him. 

Eventually having to drag himself back forward to stop the recording, not able to stop fucking himself on the fake cock even as he sent the video off to Donnie. Eyes falling closed as he continued to bounce on it. Fucking himself faster and faster, moans only growing more and more desperate. 

Letting out a surprised gasp as the tails of his mask were pulled back, his head going with them. Eyes shooting open and staring up at whoever was grabbing his mask, “Donnie, you scared me!” he whined out, letting out a breath of relief.

But that relief didn’t last long before his head was pulled back even further, Leo’s eyes drawn to the rather pissed off look on Donnie’s face. Lips set at a deeper frown than usual along with his drawn on eyebrows turned inwards. Leo gave him a small grin but didn’t say anything. 

Donnie was quiet as well, pulling him up and dragging a moan out of him, “I was trying to hold back,” Donnie said through gritted teeth, pressing Leo against the wall before finally looking down on him.

“And I thought I made it clear I don’t want you to,” he smirked up at Donnie whose face didn’t change even a little bit. With this position, Leo pressed up against the wall with Donnie trapping him against it, it was hard to not notice Donnie’s hard cock right against his face. His still very horny brain trying not to focus on it like he really wanted to.

“Please Donnie.” Leo made sure to put on his best impression of Mikey’s puppy dog eyes as he looked up at his brother, “I need your cock in me so badly.” Dropping his mouth open as he stared up at Donnie, tongue easily lolling out of his mouth.

Donnie groaned, low and guttural as he said, “Do you ever shut up?” Before Leo could respond, Donnie had already thrusted hard and fast into his throat, making Leo gag. Not that either of them cared too much. Donnie continuing to fuck into his throat, not taking long before Leo was nuzzled against Donnie’s pelvis, tongue pressed against his balls. Looking up at Donnie, eyes fluttering.

It wasn’t long that Donnie stayed still inside of him before he pulling out, gripping the sides of Leo’s face rather hard and pushing back inside. Fucking in hard and rough and making Leo gag. He had forgotten just what it had taken for him to get so good at blowjobs without gagging. All of that training now out the window as he gagged loud with every thrust past his throat. Feeling tears at the edge of his eyes and his vision starting to blur slightly.

Having to blink past it to look up at Donnie above him, pushing past the fuzziness in his brain from the lack of oxygen. Donnie’s eyes were wild and crazed, staring down at him with a small snarl on his mouth. Making Leo whine as he mindlessly humped down on the ground. Donnie quickly noticing.

“Normally you’re horny,” Donnie said, voice deeper than normal, pleasure interlaced through every word, “but this is a new level even for you.” 

Leo couldn’t help but whine once again, thankful that Donnie didn’t try and stop him. Feeling his dick pulse with every thrust against the back of his throat. 

Just as with his dildo, Donnie’s dick was so much bigger now. Leo could feel his throat bulge where it hit so far inside of him. Leo was sure he could jerk his brother off from outside of his throat. Limbs too fucked out to do much of anything but take Donnie’s dick and mindlessly thrust against the floor.

A gasp leaving him as Donnie pulled out, cock falling against Leo’s face, balls resting on his chin and the tip landing on his forehead. He couldn’t hold back the whine that left him. Panting for only a second to get his breath back before mouthing and licking at the underside of Donnie’s dick. Wanting it back inside him but lacking the words to be able to communicate it. 

But Donnie seemed to sense it, grasping his dick and Leo whined at the hope that he would fuck his throat once again. Hitting the top of Leo’s tongue with his dick, “Couldn’t even go a week without whining for my dick let alone any more time than that. Such a slut.” His voice had more humor in it than his face, still looking pissed off. Leo couldn’t get his thoughts in order, only able to whine and tried to get the dick in his mouth again but Donnie kept brining his dick away right as Leo got close enough. Leaving Leo to whine even more for what he couldn’t have.

“Fuck you look so cute like this,” Donnie groaned out as he finally fucked back into Leo’s mouth. Leo moaning around it in thanks, pulling a desperate groan out of his brother. His brother who didn’t hold back as he fucked hard and fast into Leo’s mouth once again, gripping tight to the sides of Leo’s head. Pushing him further against the wall, leaving Leo only able to sit still and take the cock ramming his throat. Not sure if he would ever be able to talk normally again. Didn’t even think he would be able to think clearly for a while with the way his brain felt like it was being pulled out of him more and more with every thrust. 

Leo lost track of time as his brother fucked his face, rougher than he had been in a while. Tears now running down his face and his gagging getting less and less common. Only gagging on particularly rough thrusts. Glad that Donnie wasn’t actually speaking as he didn’t think he would actually be able to hear anything his brother said. That thought being confirmed for him as Donnie’s said something or another. The only thing registering for Leo being the low gravel of his voice as he spoke, pulling a needy moan out of Leo that was covered up by the cock in his throat.

But it didn’t take long for him to be able to assume what Donnie had said. Donnie’s thrusts speeding up, fucking hard and rough into Leo’s throat. Going as deep as he could, cumming in Leo’s throat with a groan. Leo didn’t even taste it as he moaned, looking up through blurry vision at his brother. 

Donnie stayed still, panting down at him for a few moments before finally pulling out. It took Leo’s brain a few moments to catch up with what was happening, staring up at his brother with his tongue still rolled out of his mouth, all of the cum having been poured straight down his throat and into his stomach.

“It seemed we found something to shut you up,” Donnie scoffed, eyes narrowed down at Leo, “All it takes is to deny you for a few weeks and then your brain shuts down with even a little bit of dick like a slut.”

All Leo could do was moan, mouth finally closing. Tongue coming out to lick up the small amounts of cum that had dripped down his chin combined with his drool with another moan. Only half understanding what his brother was saying to him.

“Th,” Leo cleared his throat, voice scratchy and uncomfortable, “Thank you big brother.” 

This time it was Donnie’s brain that seemed to break, something so rare from the family genius. Neither of them, in the few months that they had been dating and even longer that they had been fucking around, had brought up the fact that they were brothers in bed. It seemed like such an obvious thing to play with and yet neither of them brought it up. And right now, with the whole situation, it had seemed right. Leo hadn’t even thought about it, didn’t think about much right now, just said what came to him first.

And it seemed to have been a good idea as once Donnie seemed to fully catch up, brain processing the words, he had grabbed Leo’s mask tales once again. Leo had forgotten he’d still had it on, feeling the fabric stick to his cheeks where it was soaked with tears. Using the grip on them, Donnie basically threw him onto the bed, face down into the covers. Showing off the strength he had alerted Leo to earlier in the month. Leo easily moaning into the bedding.

He tried to pick himself back up but quickly his face was shoved back into the bed. Donnie growling behind him, “Stay still.” Leo did not move but could feel himself leak down his thighs.

After a few moments, Donnie seemed to be able to trust him to not move as he pulled away, Leo giving a small low whine in return. Donnie only said, “It will only be a minute slut,” almost certainly rolling his eyes as well. It was a struggle for Leo to hold still.

But there was something in the back of his head that wanted too badly to follow his brother’s order. An unfamiliar feeling but one that he didn’t have enough brain power to really question. Only able to stay still like his brother asked, now holding back his whines as well.

Like Donnie said, it was only a moment that he left Leo all on his own on the bed, climbing on top behind him. Leaving Leo with a small bit of anticipation as he was left in the dark about what was going to happen next, not being able to see Donnie behind him. Only able to see the darkness of the sheets below him.

He didn’t have to wait for long however to figure out just what his brother’s plan for him was. Donnie didn’t go slow, cock thrust hard and fast inside of him all at once. Leo letting out a loud scream at the pleasure overwhelming him. 

Leo had known of course that his brother was bigger than his dildo, but now that difference in the size felt even greater. Cock stretching him impossibly wide and reaching farther inside than ever before. Making Leo’s eyes roll into the back of his head. Could probably feel him from the outside if not for the angle.

At least, Donnie had the grace to stay still for a moment. Letting Leo lay against the bed, legs trembling and sure he would have collapsed had it not been for Donnie’s hands holding him up.

But he didn’t wait long, soon enough pulling out almost all the way out, once again pausing with just the head inside. Pulling out a whine from Leo that quickly devolved into a loud moan close to a scream as Donnie thrust back inside. Keeping up a fast and rough pace as he fucked into Leo. Easily using his much smaller body like he was one of the fleshlights Leo had seen that Donnie had made himself before they had gotten together. Ones that Leo had seen his brother use and knew exactly how he did use them.

Everything about that made Leo give another weak moan, cumming against his plastron, “Only a few seconds of getting truly fucked,” Donnie said, panting, “and you’re already cumming for the forth time tonight.” 

Leo didn’t remember the second or third time Donnie had clearly seen but he couldn’t care less. Only able to moan and fuck back onto his brother’s cock. Barely even thinking beyond getting more of Donnie’s cock inside of him. Which just made Donnie chuckle more.

“Th-thank you big brother,” Leo panted out, cheek pressed against the soft pillow beneath him as he stared up at Donnie. A rather loopy smile clear on his face. Once again Donnie’s thrusts speed up. Leo very briefly thought about how he would have to remember this for next time but the thought was quickly fucked out of him with another particularly hard thrust. 

His brain basically shutting down with every thrust didn’t stop Leo’s mouth from running, nothing seemed to. Not fully realizing what he was saying, watching the way that Donnie’s face seemed to barely change at this point, eyes pointed down to where he was fucking into Leo.

“Pleash,” Leo whined out, tongue feeling much softer in his mouth than it ever had before, “Pleash, I need it. Need more sho bad.”

Donnie’s face still didn’t change but Leo could tell he was enjoying himself regardless. The way his hands tightened around Leo’s waist. His thrusts getting more sloppy by the second as he almost certainly got closer to his own orgasm. That was the one that had Leo getting excited. Brain now only able to think about his big brother fucking a baby into him.

He gave a loud moan bordering on a whine before saying, “Pleash, Pleash big brother,” he interrupted himself with another moan at a particularly hard thrust against his prostate, “pleash fuck a baby into me.”

For a moment, Leo thought he might have gone too far with all of this. Donnie stopping altogether. Finally looking at Leos face, mouth dropped down and eyes wide in surprise.

He didn’t have to think for too long however before Donnie was pulling out, making him even more worried. Almost pulling all the way out before stealing any words he could have used to beg and turned them into another loud scream as he thrust back in hard and rough. Harder than any of his previous thrusts.

The new pace even more brutal than before. Donnie’s cock abusing his insides and somehow going even faster than any other time they had done this. Yet another thing to slot away for later.

“Yesh yesh yesh,” Leo screamed, “pleash big brother. Get me pregnant for my first time! I want it sho bad!”

Tears and drool were running down his face and soaking the pillow beneath him as he begged. Now only being held up by Donnie’s hands. 

“For a supposed virgin,” Donnie panted, words trying to convey nonchalance but the tone betrayed that, filled with pleasure, “you sure act like a fucking whore. You sure you didn't fuck someone else before this? Someone else take what is the rightful property of your big brothers?”

Normally Leo would make fun of his brother’s possessiveness but it just made him sob with pleasure. Feeling himself getting closer to yet another orgasm, almost certain that nothing would come out this time, “N-no! No big brother,” he whined out, wishing his lower body was working well enough for him to thrust back against his brother’s cock, “only you alwaysh.”

Donnie seemed satisfied enough with that answer, aiming right for Leo’s prostate as he sped up his thrusts. Throwing Leo right over the edge yet again that night. Leo having been right as only a spurt comes out with a whine. Every thrust started to hurt now, finally hitting his limit.

Thankfully, it seemed Donnie was not far behind, continuing to fuck into Leo hard and rough, “Gonna fuck you so hard, you’ll be pregnant for sure.” Donnie groaned out, Leo nodding his head along, only half understanding what Donnie was saying. Only knowing that if Donnie wanted it, he wanted it.

It didn’t take long before Donnie was thrusting in as far as he could, giving small pointed thrusts as he finally came inside of him.

The two laid there in silence, panting as they came down from everything that had happened. Eventually Donnie pulling out, so much cum following after his cock, “Sorry about being so rough,” He sighed. Leo was quick to shake his head with a loopy smile, turning to look at Donnie properly as he plopped down next to him. 

“Do not worry about it,” he said, leaning over to press a kiss to his brothers check, “Maybe we should go a while without fucking more just so that you continuing to be that rough.”

“I am not doing that,” Donnie said bluntly, eyes closing, “Just go to sleep Nardo.”

Leo could have fought more about it, but the several orgasms and the rough sex had taken it well and truly out of him. Making him rather tired without Donnies opinion, “Only because I’m tired and not because you told me too.”

“Uh huh,” was all Donnie said, not even opening his eyes as he said it. Instead of fighting back like he wanted it, Leo cuddled right into Donnie’s side. Easily fitting in against him. Feeling so small next to his brother and almost said that he would hate giving this up. And then remembering what it would take from him and deciding he was fine with it ultimately.

Now that Donnie had given in, he was a lot easier to convince to have sex and with almost a month of celibacy, they had a lot to make up for. Often falling asleep rather easily with each other.

Only three days after did Leo wake up, curled against Donnie’s side like he had the last few days but feeling a lot different. Looking down at his hands to find them much bigger once again. No longer as small as he once was. Not even having to look into the mirror to figure out what had happened to him. 

“Three days!” Donnie yelled, throwing his hands up in the air. Pacing in front of the bed, having not even put any clothes on. It was probably a good thing they had fallen asleep in the bedroom shooting off from the lab which was sound proof along with being far away from their brothers.

“Yes I know,” Leo said, arms crossed over his chest, now much bigger than he remembered and feeling weird, “You’ve said it quite a few times.”

But Donnie didn’t respond to that, continuing to pace and rant about how if they had only waited a few days then Donnie wouldn’t have fucked a child. Leo rolled his eyes and decided to not mention about how it had been the child who had been pushing for it. Knowing there was nothing to stop this rant. He really wished he had a drink.