Archive of Our Own ^beta

Now, Aizawa has an incredible bladder capacity. He has to, of course, for long stakeouts and the very few breaks a teacher gets, but it goes beyond that. He regularly goes through entire school days and patrol shifts without pissing, and by the end, he's only slightly uncomfortable. He knows it's unusual, sure, but he didn't know Zashi paid so much attention to it. He honestly had no idea that his husband wanted to know how he acts when his gargantuan bladder reaches full capacity.

(If he'd known, he wouldn't have been so careful to actually use the bathroom regularly, instead of waiting until it almost hurt. He doesn't find pleasure in the desperation; it's just so much more convenient to wait until he actually needs to go. As a teenager, he only stopped when Hizashi 'slept over', because other people tended to be disturbed or worried by the solid bulge in his abdomen when he didn't piss for a full day or more, and he couldn't just tighten his belt over it when they were both naked. Once they moved in together, he quit the habit completely- except for the times when one or both of them are out of the house on some stakeout or long-term mission. So... No, he doesn't think Zash has ever seen just how much he can hold.)

So he offers to let that dream play out in real life, and smirks when Zash asks worriedly if he's sure he'll actually be able to do it. He doesn’t say aloud that he can hold for forty-eight hours at a time, longer if he pushes it; he's absolutely confident he can take the contents of Zashi's bladder along with his own for just one day. 

They do it on a Friday. Aizawa refuses to explain why he insisted on that day, and Zash relents. (If he's going to do this, he'll do it as long as physically possible, and after a certain threshold he won't be able to hide just how desperate he's going to get. He wants to give the love of his life a show that neither of them will ever forget, and he just can’t do that if he has to duck off and piss before the involuntary responses start.)

The day starts like this: Hizashi insists that Aizawa use the toilet as soon as they wake up, even though he doesn't need to go yet. Zashi, on the other hand, shifts and squirms as he waits his turn, having downed a fuck ton of water the night before.

Aizawa flushes the toilet, turns around and kneels. Zashi is strangely hesitant for someone who looked ready to cream his pants at the idea of doing exactly this, but eventually he relaxes, and the intensely bitter, salty liquid flows into Aizawa's mouth and down his throat. He struggles to swallow it all fast enough that nothing spills. He can't breathe the entire time, and pulls off coughing and gasping for air, but he doesn't waste a drop. 

"It's bitter," Aizawa complains halfheartedly, and has to reassure Zash that he's not backing out because of the taste. 

And that's how their day goes. Hizashi stays very well-hydrated---he always does, for his voice, but today he drinks more than usual---and every time he needs to pee, he taps Aizawa on the shoulder and heads to the bathroom, where Aizawa drops to his knees and opens his mouth, staring up evenly through the fringe of his hair like he doesn't know just how sexy he is. 

By the end of their lunch break, Hizashi's needed to piss three times (including that first one). Aizawa's holding all of that in addition to the coffee he had earlier. 

"Hm? I'm fine," Aizawa dismisses when Zashi asks if he needs to stop. He's filling up a little faster than usual, sure, but right now it only feels like the equivalent of a normal school day if he hadn't pissed this morning. "I can take anything you give me."

"But... What if I push you too far?"

"I'll let you know if it's too much," Aizawa offers, mostly to placate him. "Don't worry about me until then.”

Hiza still looks hesitant, so Aizawa takes his hand and places it, palm flat, over the gentle swell that marks the only evidence that he might have to go. 

“I’ll prove it to you. Go on, baby… If I’m anywhere near my limit, do you think I’ll be able to keep a straight face?”

He could, actually. He knows how to tighten his belt without even a twitch when the bulge is prominent enough to show. He knows how to keep a straight face when his bladder spasms and contracts, when his body is tense with resisting the urge to double over and rock and writhe. This will be nothing in comparison. But Zashi needs reassurance, or he won’t let himself enjoy the game. 

Zashi only presses lightly, for a fleeting moment, and then pulls back to check Aizawa’s face for signs of strain. 

“You’ll need to try a little harder than that if you really want to test me, Zash. You know how good my control is, don’t you? Come on, love… Break it, if you can.”

Breaking composure. That’s what Hizashi wants to see, so the words are more than enough encouragement. Palm flat, he braces his other arm behind Aizawa’s back to keep him still, and presses forward. Hard. 

Aizawa allows himself a soft noise that could really be interpreted any number of ways, but he keeps his posture and expression neutral. This is nowhere near the threshold of what he can take without flinching. 

“Amazing,” Zashi breathes, and Aizawa smirks.

“I know you want to watch me squirm, but I’m still hours away from that point. Maybe by tonight I’ll have enough of your piss in me to really feel it.”

Aizawa is sorely tempted to keep teasing him, but if he goes any further, Zash might end up half-hard in the middle of a school day. As it is, he’s being stared at like he’s the sexiest thing Hizashi’s ever seen. 

I never would have thought of this in a sexual context. All I know so far is that Zashi wants me to hold it, but I’m not sure why. Is it the vulnerability, the chance to take care of me even as he draws out my torment? Is it the idea of using me as a toilet while he denies me the same luxury? Or does he just want to make me beg?

It would be much easier just to ask, but that wasn’t as much fun. They were doing something entirely new; he might as well experiment with it.

So that’s the plan. He’s going to hint at each of his theories, see which one Zash responds best to, and play along until one of them stops enjoying the game. 

Aizawa may have underestimated the effects of almost doubling his liquid intake. He’s not at his limit- not even close- but his bladder provides a familiar, almost comforting weight, and he remembers now the rest of the reason he used to do this so often. It’s not arousing to him, it’s just… A good kind of pressure. Satisfying. 

Layered over the satisfaction is amusement now, because he just took his shirt off---after subtly loosening his belt, because Zash would definitely freak out if he saw how tightly constricted it was---and Hizashi’s jaw actually dropped at the sight of his abdomen. 

It’s only a few centimeters. Is that really so unbelievable?

“Like what you see?” He asks instead, and Hizashi seems to shake himself out of some sort of trance. 

“Yes. Yeah. Holy shit, Shou, that’s… God, that’s so hot, you have no idea,” Zashi breathes. 

So the bulge itself arouses him, as well. Is it the volume that I’m holding, then? Is that what he wants to know?

Ah, that’s right. I believe I made an offer earlier today, it should be about time.

“Thank you... Now, wasn't there something we planned to do?"

Zash frowns, trying to remember, but it doesn’t seem like he’s going to. Aizawa sighs, and elaborates. 

"You were worried about pushing me too far, and I asked you to... Test me. Make sure I still have room for more."

"Oh, that's right..." 

Some instinctive part of Aizawa snaps to attention at that tone. The one that Zashi never seems to notice he's using, but always threatens to kick Aizawa's knees out from under him. (Privately, he thinks of it as the Dom Voice, but he might actually die of embarrassment if he ever says that out loud.)

"Come here, Shouta."

He goes.

Zashi moves as if he's going to do it, but- only smiles and kisses Aizawa, deep and slow. He melts into it, just a little, and is caught entirely off-guard when something shoves hard against the sensitive area.

In a strange way, he might have actually given more of a reaction if he were expecting it, since he knows that Zashi wants to see him desperate. Taken by surprise, he automatically clamps down on any sort of reaction, and only closes his eyes for a little longer than a blink to focus. His breathing might have stuttered momentarily before continuing in its rhythm, but said rhythm was already broken by the kiss, so it really isn't noticeable. 

Zashi pulls back, incredulous. "You- weren't affected by that. Like, not at all?"

Aizawa shrugs, a little embarrassed. "I can't afford to be put out of commission every time I get kicked in the stomach."

"Does that mean I won't get any reaction out of you? What was the point of asking me to do that, then?" 

Aw, no, he's pouting. Now I feel bad. "You were concerned for my health. And I had planned on reacting to it..." This sounds so fake now that I'm actually saying it out loud. "Bad wording. Give me a second."

Zashi nods and rocks back on his heels, waiting patiently. 

"Okay. I wasn't going to fake a response. I'm still human, Zash; I assure you, it affected me. I just didn't respond because I've taught myself not to, and you surprised me. Suppressing any external reaction comes more naturally than showing it, at this point." Oh, there it is, I can turn this into something. "If you like, I can... Act as I normally would. You'll know I'm genuinely desperate when you finally break me down enough to squirm, then."

He knows he chose right, phrasing it like that, when Zashi shivers and nods. "You do that, Shou."

So it's the amount that I can hold, and the desperation itself... Or maybe the power? Fuck, I still don't know. 

"We have quite a bit of waiting to do, then." 

Aizawa shrugs in response to Zashi's look of disbelief, and asks casually, "Have I ever told you my record? That might actually help explain to you how I'm so calm right now."

"Record-?" Zashi's eyes widen, and he shakes his head. "No, you haven't. What is it?"

"...Eighty-five hours, give or take. Three and a half days." Granted, he was in a holding cell for exactly two of those days, and took great pleasure in baffling and concerning the police officers until they had to admit they had no evidence and release him. Upon which he walked calmly out of the building, into the nearest convenience store, and took such an orgasmic piss that he had to bite the inside of his hand to keep from moaning aloud, and even then his body twitched and trembled the entire time, eyes rolled back behind tightly closed lids. He'd been on antibiotics for a week after that stunt, but to this day it's one of the best things he's ever felt in his life.

"Hurt like hell at the end," is the only elaboration he offers when Zashi's jaw drops. And it's true. As good as the release felt, it was not worth the pain he suffered for hours beforehand. He'd only done it because one of the officers kept taunting him, asking in such a fucking condescending tone if he had to 'go pee-pee' whenever he shifted or squirmed, and Aizawa Shouta is nothing if not petty. It was immensely satisfying to watch Officer Chucklefuck's eyes bug out when he stood, bowed in thanks to the woman with the keys, and walked slow and even out the door as if he didn't look fucking pregnant. 

Even now, he's not sure how he managed that particular feat. He can barely remember the walk from there to wherever he ended up, only that he was in so much pain his eyes watered continuously and at least one person stopped him to ask if he was okay.

"But- wh- how? And when did you even do that?"

"The time I got arrested."

Zashi's flat, unimpressed look was humbling. 

"...The time I got arrested for supposedly erasing Endeavor's Quirk on live television. There was no evidence, but I pissed them off enough that they kept me there for the full forty-eight."

"And you just, what, didn't pee the whole time? I know for a fact that there are toilets in those cells, so what happened?"

Ouch, Zash. The disbelief. Aizawa shrugs. He really doesn't want to say it out loud, because his reasoning sounds childish even to him. 

"Shouta."

"...One of them made fun of me," he mutters, ears and neck already starting to burn with what he knows is a conspicuously bright flush. 

Zashi laughs at him. 

Traitor. 

Zashi sounds a little disappointed by the total lack of action, but asks him to use the toilet before they go to bed. For safety's sake, and so he doesn't have to suffer all night. 

Aizawa doesn't want to. He'd rather wait until morning, when he's sure he'll have to piss badly enough to show it. In public, that would be a different story, but after a certain point it's a conscious decision instead of an automatic suppression, and he really wants to see Zashi lose his goddamn mind. 

So he lies. And asks his love to use his mouth once more, promising to relieve himself afterwards. 

He waits for the split second when Zashi looks away, and his hand darts down to grab one of his thicker belts. It's wide, and it might just be enough to keep his bulge invisible if he wears one of his oversized shirts. 

He holds his breath for a few seconds, tightening the belt until his bladder screams in protest, and waits for it to settle. 

It's just for a minute, he promises himself, and I'll take it off.

Loose and relaxed, he curls into Zashi's arms, drawing his knees up so he can take the cursed thing off without risking discovery too soon. 

As always, it's easier to fall asleep than it probably should be. 

Aizawa wakes up slowly at first, squinting angrily at the sun and hoping that this time, the curtains might close themselves. 

They do not. 

Bastards.

Oh fuck he has to pee. 

He's had worse. He knows he has. But after a full day and night of holding double the amount of liquid he'd drink on his own, he's already reaching the point where he'd be really struggling to hide his need in a public place, even if he wasn't belted. 

But this isn't a public place, and more importantly, he doesn't want to hide it.

So he starts to reach- and realizes with a jolt that he's already got a hand on his dick. A fist, really- goddamn that's a tight grip, how didn't he notice?

Situational awareness, Shouta. Honestly. 

His bladder pulses, a not-so-gentle reminder, and he muffles a groan into his pillow. 

...ngh.. 

His mouth is dry. 

He gets up, and drinks a glass of water as quickly as possible, stiffening at the feeling of it draining directly into his aching bladder, fatigued muscles quivering and threatening to-

Aizawa breathes, presses his thighs together, and slips back into bed. 

It looks like... The slight motion of his return was enough to wake Hizashi. 

That's good. Would hate for him to miss the show, when he's the entire audience. 

Slowly, carefully, Aizawa lets up on his iron control over every move he makes. He allows his breathing to shorten, his thighs to press and rub together, and- no, not his hands. Not yet. Not yet. 

Zashi snuffles and yawns, sleepy eyes blinking open and narrowing as he takes in the apparently sleeping, but obviously distressed form of his husband. 

"Shou?" He whispers. "Are you awake?"

Aizawa cracks one eye open, and nods. 

"What's wrong?"

Aizawa smirks, wide and satisfied before it twists into a grimace. He didn't mean to do that- but it's alright, because Zashi's much more alert now, looking over the part of him that's currently visible. The way he's shifting and squirming in place, just a little. 

"Oh, Shou. You didn't."

"I did. Or... I guess I didn't," he huffs at the dumb little joke. "'m not sorry. Promised you a show."

"You also promised you wouldn't push yourself," Zashi scolds, and Aizawa grumbles, but doesn't know how to argue against that. 

"...Does that mean you don't want to make me-" beg for it? Fuckin' half asleep brain. I almost said that out loud. "-lose the control you were so frustrated by last night?"

Predictably, Zashi thinks with his dick. "Fuck, yeah- but. I won't hurt you, will I?"

"'course not. I know I lied before, and I'm sorry, but I promise I'll stop you if it hurts." I really will. That kind of pain is never worth it. 

"Okay, then. How do you want to do this?"

Aizawa's already thought of that, and mentally rehearsed it enough that his voice is smooth and low as he says, "I want you to fuck me, Zash. Press on my bladder from the inside, harder and harder until I can't stay quiet anymore."

Zashi gasps, and he knows he's won. 

They take a moment to shove everything off the bed--it's just the logical thing to do, so there's less to clean up afterward--and Aizawa turns around, curious, when he notices that Hizashi isn't moving to help. He's just... Standing there, looking torn between dazed arousal and worry. 

"Zash?" Is something wrong?

Zashi makes a strangled noise and gestures back at Aizawa. 

...Helpful. Really. Now I know exactly what you meant. "Care to elaborate?"

"Your- that should not be physically possible. You look pregnant, Shou!"

Aizawa looks down at himself, at the immense bulge marking almost four liters of piss inside him, and immediately remembers why he tries to avoid doing exactly that. Visual reminders of how impossibly full he is- of how far past the average human limit he's gone... They don't exactly help. 

The opposite, in fact, and he has to close his eyes and take several slow, shallow breaths before he can comfortably move again. 

It's unreasonably difficult to relax enough to prepare himself, but he manages with minimal complaint, keeping his eyes on a practically drooling Zashi the entire time. 

He lays back, lets Zashi position him, an-d-

ohf-fuck-

so full... hnngh...

He's. He. Full. In a way he's never been before. Not like this. His cock twitches, trying to harden even though he has to piss so badly it's just not going to happen. 

He's panting, he realizes, even though Zashi hasn't moved yet, and is- he's- worried. Looks worried. 

"I'm okay," he says, cringing at how breathy his voice is. He clears his throat and tries again. "It's fine. Just." Nothing's even happening- why is it so intense? "You can move."

"You sure? You look a lit-"

"I'm not fucking begging you, Hiza, move." Or I might just make myself a liar. 

...ah, fuck. I called him the name. 

And Zashi hasn't missed the implications. They both know Aizawa only uses that nickname when he's starting to feel submissive, which usually only happens during actual, controlled play, not casual sex.

"Oh..?" Zashi recovers admirably quickly, rolling his hips forward in a way that has Aizawa trapping a whine behind gritted teeth. "Feelin' subby, Shou?"

"s possible," Aizawa admits. "I'm... not sure why-a-ah! Come on, don't do that when I'm trying to talk." 

"Do what? This?"

Zashi drives in deep again, hitting his prostate dead-on and, as promised, pressing hard on his bladder from the inside. Aizawa gasps out a shaky moan, the part of his mind that didn't just go blank working distantly to figure out why it felt so good. 

He didn't stop this time, to say anything else, even to mess with Aizawa. He set- set a punishing pace, pushed Aizawa's knees up closer to his chest for a better angle, and- he- fuck, Hiza-!!

He's. Struggling. Trying not to, because he doesn't want it to stop, but his body keeps making these little aborted jerks, trying to twist away before he stops himself. It doesn't hurt. It's not- bad. It's just so much. He's sure he looks like a mess already, every other breath carrying a hitching whine or a choked-off sound that might have been a word before he cut it off, but he just can't care. He can't, when his thighs are digging cruelly into the immense bulge of his bladder, when Hiza's inside him and adding to the pressure, turning it all into pleasure that burns through his veins, every movement, every little noise adding to it, building higher, faster, f-fas- more- 

Hiza's hand presses down, and a strangled cry of pure pleasure resonates from every inch of him. 

Everything... Slows down. Shouta gasps for a longer breath, slower, and opens his eyes to see what's wrong, why they're stopping. 

"You okay, Shou? We can stop-"

"Don't." Don't stop. Not now. God please don't stop, it's so good. "I'm- f-fine."

"You're not, lovely." 

Aizawa almost whines at the pet name, and turns his head into Hiza's hand, only to realize why the hand was put there in the first place, because it smears something wet beside his eye. Apparently he was, in fact, overwhelmed enough to start crying. But it was just- he's just overwhelmed. It doesn't hurt. 

After an eternity that lasts all of three seconds, he says so. 

"You're never this vocal, sweetheart. This- it's great, but it's not normal. You're sure nothing's wrong?"

Hiza doesn't believe him. He doesn't- but he meant it- I was telling the truth- ple- don't stop now- don't- I- H-Hiza please- (sorrysorrysorry)

"Oh, baby, I didn't know you were in that deep." Hiza leans down to kiss him, and he whimpers into it because the cock inside him shifted and sent sparks of pleasure-pressure-pai-?- rushing through him again. "Tell me what you're feeling, and I'll fuck you the way you want."

Aizawa shudders, and answers. He's- he was. overwhelmed. 's so much. Not too much, but almost there and it's so good and he almost has to pay more attention to not pissing himself than he does to anything else even though he should be fine, really- there's. No room in his head for anything else, anything outside them. 

Hiza likes that answer, and Aizawa knows it because he calls him good and- and he starts to move again. And Aizawa- is- gone. Has very little idea what he might be saying, only that he is, and it may or may not be even a little bit coherent but he's leaning towards not because his thoughts sure as hell aren't. It builds, and builds, whatever it is, and reached the point they were at before- passes it, and. 

And for the first time in what might be actual decades, Aizawa leaks without meaning to. Loses a spurt of piss, running hot down the tight skin over his bladder, and the wetness is torture and he loves it, but not enough to do it again. It's- the decision is take out of his hands soon enough, put into Hiza's- literally, as a hand is back on him, on his bulge, rubbing and almost-petting-? weird- and pressing down until the tension snaps in the form of a second, longer leak, and a broken little moan that twists up into a whimper at the end, when Hiza digs his fingers harshly into the swollen organ. Aizawa doesn't get the chance to stop it this time, and the leak that was supposed to end- doesn't. All he can do is slow it down, slow it, hold back as much as he can until it's just dripping, just a little at a time, not sure anymore why he can't let go, knowing only that he can't. Can't. Shouldn't. Wants to, gods he wants- no, he needs it, so bad but he can't, can't- hold it- because- because..? Hiza wanted it. Hiza wants. H-Hiza... Please- I-I can't, I- can't- gotta- hizapleaseplease

"You can let go, lovely, I'll take care of it."

of what?

oh- I can- I- 

Aizawa bucks into the next harsher press, grinds back, and waits just a little longer, a little more, until he sinks fully back into his role and the pressure overwhelms him again. 

This time, he doesn't resist it. Lets it take him, control him, whimpering and writhing and sogoodtoogoodpleasepleasemore and he's wet, soaked, in his own piss and it should be disgusting but it's not, gods it's not, it's just so good... yess....

Even after he's empty, he's full, Hiza still inside him, grinding in the little irregular circles that mean he's about to cum. 

I did that, Aizawa thinks, immensely- rightfully- pleased with himself. His own neglected cock twitches again, hardening quickly, and he almost mourns it because he won't get to cum when Hiza does, or before. But Hiza hears his thoughts somehow, or maybe he's still babbling, and goes still with a halfway-pained grunt that means he was really close. And- ngh- grabs Aizawa's half-hard length, rough, twisting, taking him back to the edge of too much, too good- too much- so good please- and. And they come, at almost exactly the same time because Hiza shudders and bucks and moans when Aizawa clenches up around him.

"So we're doing that again."

"Yeah."

"...Maybe not on the bed, though. Unless we buy a better mattress cover."

"You think."