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Bakugou didn’t think that adjusting to Kirishima’s body would be so difficult. Being hit with the body swapping quirk while just trying to study on a Sunday outing was an annoying setback since they couldn’t train until it was over, but he hadn’t been anticipating actively struggling with usually thoughtless day to day tasks.
First off, Kirishima’s body ran extremely hot. It started to make sense why he would always walk around shirtless, it felt like he was going through hot flashes constantly, and coming from someone with a fire based quirk who loved spicy food, that was really saying something.
On the topic of food, it was so difficult to eat any solids at all. Not every single one of Kirishima’s teeth were spiked, his molars flat, but trying to chew anything while having such sharp and particularly angled teeth was a learned skill Bakugou never needed to acquire. It hurt when he got the angle off, often biting his tongue (which was particularly bad since he didn’t have hardening instinct) or even the inside of his lips.
Bakugou’s body wasn’t physically weak even in the slightest, but Kirishima had bulked up over the years to help along the development of his quirk, meaning his natural strength had surpassed Bakugou’s. Their friends often joked Kirishima didn’t know his own strength whenever he’d half squeeze them to death with a mere hug, but Bakugou literally didn’t know the strength of Kirishima’s body and had nearly pulled multiple doors off their hinges simply opening them.
Last but not least, the absolute worst thing about trying to settle into Kirishima’s body, was his fucking dick.
Getting an occasional glance at it in the locker rooms and actually having it were two completely different things. Especially when Bakugou was trying his goddamn best to respect and do right by Kirishima’s body. He would wash it when he bathed and hold hold it when he pissed, but fucking christ almighty was it goddamn frustrating to do any of that while attempting to keep his mind completely clean.
That wasn’t even the end of it. Throughout the days he had to constantly readjust so it wasn’t creating a bulge in his school pants, tucking it into the underwear while trying to look inconspicuous. It’s like he could feel the weight of it between his legs at all times, so much heavier and thicker than what he was used to dealing with.
He only didn’t get boners out of sheer willpower and determination. If he got hard in Kirishima’s body, it would be so painfully obvious, especially to the man himself who was occupying his own body.
Over the course of the week, Bakugou couldn’t help but notice new minute things every time he showered. Like how big Kirishima’s hands were to be able to wrap perfectly around his thick dick, how heavy his balls were between his gorgeous beefy thighs.
It was one thing to have a crush on Kirishima, which he’d come to terms with long ago, but getting to know his body on such an intimate level like that when he couldn’t physically put his head down and get an actual closer look wasn’t far from physical torture. He wanted that damn third leg in his mouth and those balls smothering his face.
All that thinking about sex was pretty new to him, he was usually so focussed on his hero goals that he didn’t have time to. The way he then couldn’t get his mind off of what was between Kirishima’s legs had built up a frustration he’d never felt so intensely before.
He promised he’d take care of Kirishima’s body. Letting it get pent up and frustrated like that wasn’t doing so. Every time he willed down an erection or ignored the starting sparks of one, he swore he could feel Kirishima’s balls swell and pulse like they were mad at him.
The second he let his guard down, it was over. No amount of hoping it would go away could get rid of it when his heart wasn’t even slightly into the sentiment.
—
It had been over a week and Bakugou struggled to admit that everything was only getting harder. Quite literally, he’d had to sleep off the last couple boners Kirishima’s body attempted since nothing he usually did was working as well. Was Kirishima always this ready to go and horny, or was it really all just Bakugou being more affected than he let himself admit? Fuck if he knew.
But he’d been fairly lucky with the circumstances. It was only a matter of time before he got the opposite end of the coin.
Dinner was supposed to be really soon, and even in Kirishima’s body, Bakugou had grown comfortable taking the head role for cooking for the large group and was relied on to do that. He couldn’t just not show up, but he couldn’t show up with an all too noticeable hard-on either, which was the direction things seemed to be going as he stared in horror at the tent slowly peaking at the crotch of Kirishima’s body.
For fuck sake, he didn’t have time for this! It’s not like five minutes in a cold shower would make it go away and focussing on something else or sleeping it off weren’t quick jobs either. If he wanted to turn up to dinner without it being completely inappropriate, he had to make it stop in the quickest way he knew how. The second he even considered it, the arousal in his stomach turned from a simmer to something more fierce, Kirishima’s body responding accordingly.
Fine. He just had to do it this once because of the circumstances. At least he knew how quickly it would be over if his eagerness was any indication.
His heart pounded as he lied back on the bed, upper back propped up by a couple of pillows, giving him a perfect shot of the way Kirishima’s abs crunched slightly, a healthy layer of fat cushioning them. Lightly scraping his lip with his teeth, Bakugou placed a hand on top of Kirishima’s stomach before slowly snaking his fingers past the waistband of both.
Taking a deep breath, he ripped the band aid off, shoving his pants and boxers down and off in one quick motion and almost moaning when Kirishima’s dick slapped heavily and audibly against him.
Compared to his own, it was darker and redder in color, thick and trimmed black hair running from his happy trail to his pubic area. Seeing it almost fully hard shot arousal through him itself. If he had the time he would get to know it in every single state, regretting that he hadn’t already done so, since at least for now he was supposed to be hurrying up.
Wrapping one hand around it, Bakugou gawked at how well it still fit in Kirishima’s big palm, that proportionately it didn’t look or feel much different to when he touched his own, but knowing the difference would be jaw dropping if they were to actually see them together. Literally jaw dropping, since Bakugou had wanted it in his throat since two years ago and this was only helping his future fantasies get all the details right.
His breath turned heavy as he slowly squeezed Kirishima’s dick in different ways, twisting and pumping his hand from multiple different angles until he found the best ways to pleasure Kirishima’s body, which he’d quickly learned was fast flicks of wrist around and under the head paired with the occasional teasing slow drag all the way down to brush his balls with the outsides of his fingers. It felt so amazing, Bakugou sure he was going to tear through Kirishima’s bottom lip with how hard he was biting down on it in attempt to prevent making any sounds, as much as he wanted to hear them.
He propped both his feet on the bed and bent his knees so he could thrust up into his hand, drawing his attention to the way the muscled thighs clenched at either side. What he wouldn’t give to be trapped between them with his senses filled to the brim with Kirishima. His weight, his scent, his taste— fuck! He was definitely right, this was not going to last long.
The sounds coming from the slap of hand against cock were obscene and loud, almost sounding like Bakugou’s own explosions to his ears.
Realising he had a hand free and how that was a wasted opportunity, Bakugou immediately took to it to fondle Kirishima’s balls, not able to hold the moan that caught up to him because of it. Shit, they were much more sensitive than his own, pulling and rubbing on them caused his stomach to constrict in warning that his fun was very soon going to come to a finish.
The tip of Kirishima’s dick was turning purple in need and Bakugou jacked it faster and harder, thrusting up into Kirishima’s calloused palm like it would kill him not to.
Is that what it would be like to ride Kirishima? Would he grip Bakugou’s waist with those perfect hands and slam into him just like that? Fuck, with the curve of his cock the head would probably kiss and rub so perfectly over his prostate, stretch his walls to a width they’d never experienced and likely never would again. All for him.
Bakugou started to notice just how hard he was biting down on his lip, the sharp pricks of pain mixing with all the pleasure only to amplify it more. He couldn’t stop, already addicted to the adrenaline high it was giving him despite the taste of blood on his tongue. Kirishima would be able to do that, too, mark him up and bury his teeth all over his body to take him to the top of his high that was sure to crash at any second. He could growl into his neck, nibble on his earlobe as he releases inside Bakugou’s willing body and— oh fuck he’s gonna cum—
With an all too loud moan and hips stuttering beyond his control, cum burst from Kirishima’s dick, landing in multiple spurts across his abdomen. Bakugou was still lightly whimpering in the aftermath, continuing to gently fondle Kirishima’s balls after he’d already let go of his cock.
It was quite the sight to take in, cum pooling and cooling into the divots of his abs as his thighs were still twitching as he attempted to get his breathing back on track.
That was without a doubt the best and most overwhelming orgasm he’d ever had... and it wasn’t even in or from his own body.
His limbs felt so heavy, his arms dropping to lie beside him as his legs slid out, too. All he wanted to do was clean up and get a great sleep but the now annoying responsibility of dinner was nagging at the front of his brain. When he did this again, which he absolutely was going to, he’d take his damn time and allow himself to bathe in the afterglow.
Just as he was starting to recoup properly, able to think about what he was actually making for dinner, the heaviness he felt in his body completely took over, and he blacked out entirely.
When he awoke, it was with a disorienting start that was similar to waking from an intense nightmare. He looked around in a panic, struggling to process that he wasn’t in the same situation he was before he passed out.
It hit him all at once what had happened. He was back in his own body now, fully clothed and sitting at his own desk. Kirishima’s phone was on the desk and when he checked the time on it he knew that it couldn’t have been longer than a couple of minutes since he’d been in Kirishima’s body.
Which meant that the actual Kirishima in his actual body, went back to it in the state he’d left him in and Bakugou had no clue how to feel or go about it, knowing that at that very second Kirishima was likely either about to burst through the door yelling at him or would simple never talk to him again.
At the very least, it was sure to be one awkward dinner.