[NSFW] FIC - "Lie In It"

BKDK | canonverse | UA third years (they're 18) | established relationship | quirk accident

It's not a sex quirk. Izuku is just a horny loser.

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LIE IN IT

“Where’s Deku?”

Recovery Girl didn’t even bother looking up from her clipboard when Katsuki barged into her office. Instead, she calmly finished scribbling down notes and ignored the sound of Katsuki gnashing his teeth.

Finally, after his fists had begun smoking, she said, “He’s in solitary confinement.”

“Why?” he demanded. “What happened?”

All he knew was that some second-year business student had a death wish because they had confessed to his nerd. Izuku had turned them down, obviously, but being the bleeding heart he was, he’d conceded to a conciliatory hug.

And like the suicidal moron they were, they’d used their quirk on physical contact with him. What that quirk was, however, no one would tell him, and it was pissing him off.

“I can’t tell you,” she said, looking up from her notes to look at him over the rim of her glasses. “But I’ll let him know you stopped by.”

Katsuki fumed. “I’d rather you inform his emergency contact.”

“We’re waiting to see if the situation resolves itself first.”

“Then I’ll save you the trouble. You can tell me now.”

Recovery Girl regarded him in silence. Then she turned back to her desk and removed a folder from beneath the clipboard. After briefly flipping through its contents, she paused on a page, frowned at it, and then stuffed everything back inside the folder.

“Midoriya has you listed as his emergency contact,” she said thoughtfully.

“Yeah, no kidding,” he spat, impatient. They were both eighteen, which meant they could designate their own emergency contacts. They no longer had to default to their parents, although obviously they were next on their list of contacts.

“Very well. Come with me,” she said, before hopping off her chair.

She led him through an entrance that opened with her badge, and then down a short corridor to another door that required a swipe of her badge. When the light above the handle flickered green, she pushed it open and gestured for him to enter first.

Warily, he did. It was an observation room, narrow and bare except for a chair against the wall, opposite a full-length two way mirror. Through the glass, he had an unobstructed view of a larger room, furnished with a sofa and coffee table. Sprawled on the gray sofa cushions was Izuku.

“The hell is this?” Katsuki asked, turning furious eyes to Recovery Girl.

She was unfazed by his temper. “The quirk induces through physical contact what we would consider a primal instinct. Oftentimes, it’s harmless if a little embarrassing. For example, when their quirk first activated, the neighbors had to call in the police because their dad was upturning garbage bins in search of materials for the nest he’d built in their living room.”

Sneering, Katsuki gestured with a jerk of his chin toward Izuku. “So what’s wrong with him then?”

“Evidently, Midoriya was overcome by the instinct to, ahem, reproduce.”

Katsuki stared at her, mentally running through her explanation again though he’d understood perfectly well the first time.

“So the fucker who did this was hoping to get Izuku to…” He couldn’t even complete the thought before rage turned his vision red. He would kill them.

“We don’t think so,” Recovery Girl assured, sounding maddeningly calm. “We think they only wanted to embarrass him for the rejection. They can’t control which primal instinct they unlock—that’s dependent on the victim and whatever their subconscious feels is the most urgent need.”

On the one hand, he still wanted to kill the fucker responsible for this. On the other hand, the shitty nerd’s most urgent need was… to fuck? Oh, he was so going tease the ever loving shit out of him.

“We’re told the quirk shouldn’t last more than a day. You may stay if you’d like, although I wouldn’t recommend going in there with him.” She gestured to a door at the far end of the room that evidently led into Izuku’s side.

With that, she left, the lock clicking behind her. Only slightly less homicidal, Katsuki tossed his backpack onto the chair before stepping up to the mirror. In the other room, Izuku had yet to move from the sofa, but he clearly wasn’t asleep.

He twitched restlessly, chest heaving, one arm thrown over his face. He was still in his school uniform although he’d discarded his jacket and tie. His familiar red sneakers lay messily on the floor beside the sofa.

While the idea of Izuku being unbearably horny amused him, in reality, Katsuki hated that this had been inflicted on him. But waiting it out as Recovery Girl said seemed to be their best option. Sighing, he rested his temple against the glass and watched as Izuku sat up. He looked flushed and sweaty, his hair a mess and his collar unbuttoned.

Katsuki probably shouldn’t be watching this. It felt… not quite right, even though he and Izuku had been dating for over a year now, and he really only wanted to monitor the other boy for any new side effects.

Izuku reached for the pitcher of water on the coffee table, pouring himself a glass before greedily gulping it down. He went too fast though, and water spilled over his jaw and neck, soaking his shirt before he set down the emptied glass. The water barely seemed to help. The nerd looked positively parched.

Grimacing, Izuku clawed at the buttons of his shirt. When his fumbling fingers refused to work, he gripped either side and tore it open, scattering buttons across the floor and coffee table.

An uncomfortable heat unfurled low in Katsuki’s belly as Izuku stripped off the ruined shirt and tossed it aside. Then he collapsed again onto the sofa and ran his hands over his bare chest. Katsuki watched, transfixed, as Izuku plucked his nipples and arched into the sensation.

Green eyes were closed, head resting against the back of the sofa, pretty neck begging to be bitten. In fact, there were still a few purpling marks from the last time they’d fucked. With a moan that was perfectly audible through the room’s sound system, Izuku pressed the heel of his palm to his crotch.

“Fuck,” Katsuki mumbled before forcing himself to look away. Sure, he loved watching his nerd jerk off—and Izuku loved having Katsuki’s eyes on him—but that was with his full consent.

Izuku was caught in the throes of a damned quirk. He wasn’t in his right mind to consent to anything, much less being watched while he was vulnerable.

Grabbing the chair, Katsuki deposited his backpack on the floor and then set the chair against the mirrored wall, back to the viewing glass. He sank onto the hard seat, arms crossed. He wasn’t going to watch, but he would have to listen. That way, he could still react if anything unexpected happened.

Just listening to the nerd was still torture though. He knew every whimper and moan, every gasp and soft cry. He’d wrung those sounds from Izuku himself more times than he could count. 

Shit, he was getting hard. He dug into his backpack for the book Present Mic was making them read in English. Some Shakespearean crap that Katsuki already finished a week ago, but he sorely needed a distraction. He flipped through the pages to find a section he’d highlighted as more interesting than the rest.

And then Izuku gasped out, “Kacchan!”

Katsuki’s throat went dry, and the book fell from his hands, nearly smacking into his dick that was prominently tenting the front of his uniform slacks. Izuku moaned his name again, and no force of nature could have stopped him from turning around.

In the other room, Izuku had shifted to lie down lengthwise across the sofa cushions. He’d lost his pants, and his boxers were shoved down just enough to sit beneath his  heavy balls. His dick was gripped in one fist, jerking fast and rough.

“Kacchan, please,” he whined, lips bitten cherry red. “Please, it hurts. It hurts, Kacchan, please!”

That did it. His nerd was in pain from that goddamn quirk, and Katsuki simply couldn’t be expected to sit and listen to his suffering. Not when he was right here and capable of giving Izuku some relief.

Before he could change his mind, he moved to the door separating their sides of the two way mirror, and jerked it open. It wasn’t even locked.

He had a feeling Recovery Girl might have expected this to happen, so he decided not to feel guilty as he stepped into the other room. Besides, if Izuku said no, he would leave. He wasn’t the one with quirk-induced horniness.

At the sound of the door opening, Izuku sat up, glazed eyes wide with alarm. But when he recognized his visitor, the look that came over his face gave even Katsuki reason to pause. But it was too late by then because there was a flash of green lightning and then Izuku was on him.

“The fuck,” Katsuki managed, the back of his head hitting the mirror as the other boy tore at his belt.

Before Katsuki could get a proper grip on the slippery little shit, Izuku had gotten his pants down and out of the way. The sudden constriction of fabric around his knees nearly had him tipping onto his face.

His nose never connected with the floor. Instead, his world tilted and he found himself on his back, staring in bewildered disbelief up at Izuku, who was sinking down onto his cock with only spit and a can-do attitude to slick the way. To Izuku’s credit, that seemed to be enough as he moaned wantonly and immediately started bouncing.

Katsuki gasped, his fingers digging into thick, powerful thighs that flexed and tightened above him. Izuku’s cock smacked his abs obscenely every time he slammed down, leaving a wet smattering of precum from the leaking tip. Muttering a litany of curses, Katsuki clenched his jaw from the sudden onslaught of stimulation.

Izuku was so damned tight, clearly not having prepped before unceremoniously spearing himself on Katsuki’s dick. His ass was so hot, walls gripping him with near painful pressure. This was not how Katsuki had imagined this going.

He couldn’t complain though. He’d wanted to be useful, and now he was. Izuku was using him as his own personal dildo, and to be honest, he looked incredible doing it. Every inch of his skin was covered in a fine sheen of sweat, and his curls stuck wetly to his temples. Those large green eyes were more pupil than iris, half lidded and delirious with lust.

“Izuku, slow down,” he said through his teeth. “I’m gonna—”

He almost swallowed his tongue when Izuku slammed both palms against the floor at either side of his head. Looking half-feral, Izuku snarled, “Don’t you dare come yet, Kacchan. I’m not even close to being done with you yet.”

Well. Okay then. Izuku edged him for so long that by the time he was allowed to come, Katsuki was pretty sure he’d reached a new plane of existence, a state of enlightenment in which he was perpetually horny and at peace with it.

The next morning, Recovery Girl found them in a heap on the floor, covered in all manner of bruises, bite marks, scratches, and bodily fluids. They were absolutely wrecked.

Once she cleared Izuku to leave, it took Katsuki a good fifteen minutes to convince  him to emerge from the depths of his mortification.

”How do you feel?” Katsuki asked, attempting and failing to disentangle their limbs.

Izuku groaned. “Like I rode your dick all night.”

“Yeah, I think it’s chafed. You’re banned from my dick for a week.”

“But Kacchan!” Izuku’s head at last popped up from where he’d been buried against Katsuki’s neck. His curls were matted flat on one side. “That’s not fair!”

“Take it up with that asshole who quirked you.”

“Fine.” Looking determined, Izuku rose on unsteady feet and began hobbling around in search of his clothes.

He still wanted to explode the extra who did this, but watching Izuku do it would be way more satisfying.

~fin