[NSFW!!!] 8 Simple Rules (for screwing my Childhood Friend) - Chapter 3

Chapter 3: "Whoever falls in love first, loses."

Katsuki reached under the bed, cheeks flushed pink, and Izuku cocked his head to the side as he watched. Ever since Izuku had knocked on the dorm room door, Katsuki had seemed oddly nervous, and Izuku was starting to wonder if he should ask the stupid question, even at risk of getting Katsuki all riled up and angsty.

"You asked me to show you," Katsuki mumbled, as he pulled out a plain cardboard box. "How I, um... You know, get off. When you're not here, obviously."

Izuku leaned forward, his interest piqued, and watched Katsuki pull out a slim black device, long and ribbed and slightly curved. He grinned, reaching for it, and Katsuki pointedly avoided his eyes as he handed it over.

"It's so little, Kacchan, I thought you'd want something bigger. Stuff your little hole full to bursting, y'know?"

"Shut up."

"Wait, and you used this with no lube?"

"Yeah?"

"Oh my God, you have a death wish. You must have been really desperate, huh?

He grabbed Katsuki by the shirt and hauled him in close, smirking as he glanced at the device in his hand.

"Where's the switch, Kacchan? How do I make it go?"

"Phone app," he grumbled, reaching for the bedside table. "You want to try it out?"

"Yeah, that sounds fun."

Katsuki pulled the app up and handed it to him, pointing out a couple of buttons on the screen for strengths and timers and patterns. He must have spent good money on the thing, Izuku mused to himself, he'd never have guessed it. Not from Katsuki.

"Easy enough," Izuku agreed, shoving Katsuki onto the mattress and reaching for his belt. "They make it pretty foolproof, huh?"

"What are you doing?" Katsuki demanded, squirming as Izuku tore his pants off and tossed them aside. "Why are you- Wait- Haaaaah?"

The both seemed to catch on at the same moment, staring at each other in silence, before Izuku began to laugh.

"Did you think I was gonna sit here and fuck myself on a toy while you watched?" he cackled. "No, Kacchan, I want to try it on you."

"Wha- I didn't- I meant-"

"You told me it was fun, I didn't think you'd have an issue with it."

"N-No, I mean, it's fine, I just-"

"Oh good," Izuku returned to stripping Katsuki, all his fears assuaged. "Relax for me, then."

"Ugh."

"Be a good boy for Master," Izuku teased. "I promise I'll make you feel really good."

He reached for the lube, soaking up the device to show Katsuki how it was supposed to work, and wrenched Katsuki's legs apart without a hint of consideration for Katsuki's modesty – or what shards of it were left, anyway. He muttered to himself as he devised his battle plan, making Katsuki growl, but it lacked the bite it usually held.

"Remember the safe word?" Izuku asked, as he rubbed his thumb at the tight little opening between firm cheeks. "Tell me."

"Katsudon."

"Good boy."

"Enough with the good boys."

"Do you need higher praise?" Izuku teased, leaning in and nipping at a pert nipple. "Want to hear how good you look when you're lying under me and waiting for me to tear you apart? Want to know how gorgeous you are when you're so needy and desperate that you'd probably beg if I asked you to? Need me to tell you how your little whines and moans make me so hard I could probably knock a villain out with my erection alone?"

"Good boy is fine."

"You sure? I don't mind."

"I'm sure."

"You don't have to pretend, Kacchan," Izuku informed him, cupping the hard dick in his hand and rubbing lightly. "I see how you respond. You have a thing about praise, don't you? What do they call it, is there a weird scientific name for it? Just a praise kink?"

"I do not."

"Are you sure, Kacchan? Because you spent your whole life being told you were amazing, by me and by everyone else around you. That doesn't happen as such since we've been at high school, right? So it's special now, when it happens. Right? It's okay, you can tell me."

"Shut up."

"Don't you want to be good for me, Kacchan?"

Katsuki's traitorous cock twitched in Izuku's grip, and a slightly concerning smile spread across Izuku's lips. 

"You look so handsome like this, Kacchan. All flushed and nervous and pretty, it's perfect."

"Cut it out and jerk me off, prick."

"I'm gonna do better than jerk you off, Kacchan. You've been so good lately, haven't you? Been working so hard in class, getting such good test results, even helping people, right? I've seen you helping your friends study. You're such a good boy."

He punctuated the words with a little squeeze at his throbbing member, finally taking pity when Katsuki moaned and bucked up into his touch, his face and chest burning bright red. He'd made his point, and that moan had made Izuku pretty keen to get started too, so he took the vibrator and began to slowly push it into Katsuki's hole.

The muscles squeezed tight as the intrusion began, but Izuku stroked at soft thighs as he waited, and soon Katsuki was relaxing again, letting the device go a little deeper. Izuku had all the patience in the world for this, seeing Katsuki squeeze his eyes shut and clutch at the blankets, gnawing at his lower lip to keep the noises in. 

When the vibrator was seated in nice and deep, Izuku reached for the app, contemplating his options. 

"How do you want it, Kacchan?" he asked, leaning in to bite the side of his neck and earn himself a whine. "Hot and heavy from the outset? Or do you prefer a slow, steady climb that ends in a beautiful crescendo?"

"Shut up," Katsuki gasped, turning his head away stubbornly. "Don't talk to me like that. Shit. Stupid nerd."

"Wrong answer."

He lifted one of the tense legs, slapping his hand down on the exposed buttcheek. The sound echoed wonderfully through the room, and blossoms of red appeared immediately on the pale skin. 

"Shall we try this again, Kacchan?"

"Fuck off."

Izuku flipped Katsuki onto his stomach, hitting the highest number on the phone before he spanked Katsuki's tight little ass again, yelps and moans only muffled by the pillow Izuku stuffed his face into with his free hand. There was a damp patch spreading on the sheets that Katsuki vehemently denied in his mind, unable to vocalise the words, so settling for yelling at the nerd in his head instead. 

"Are you gonna behave for me, little whore?"

"Fuck off."

Izuku sighed, rolling Katsuki onto his back again to meet his eyes, leaning forward over the pathetically dripping cock and turning the vibrator right back to zero.

"You're not gonna make this easy, are you?"

Katsuki's eyes glittered with something Izuku hadn't seen before. It was different to their usual arguments, not like Katsuki's normal stubbornness. It was almost like Katsuki was challenging him. Daring him to make his Kacchan submit. 

And Izuku was never one to back down from a dare.

"Hands," he demanded, pulling both wrists up over Katsuki's head. "Keep them there or I'll be tying them up, understand?"

Katsuki nodded, and Izuku took a firm grip on his chin, dragging his head up so their eyes met.

"Answer me."

"Yeah, whatever."

"Properly."

"Or what? What are you gonna do, Deku?"

"Maybe you can wear this," Izuku shoved at the vibrator firmly, watching Katsuki tense up, "down to dinner with your friends, while I keep hold of your phone."

"You wouldn't."

"Try me."

Katsuki's eyes flashed with indignance, as if he might argue, then darted away just as quickly, suddenly finding something incredibly interesting to stare at on the floor.

"Or maybe I'll suck a nice big bruise right here," Izuku continued, digging two fingernails into the side of his neck. "Where everybody can see it."

Katsuki didn't speak, so Izuku conceded his grip, letting blond hair fall back to his pillow.

"So let's try this again, Kacchan. You're going to keep your hands above your head, just like this. Is that understood?"

"Yes, I understand."

"Much better."

He turned the vibrator to low, making slow, steady thrusts, in and out of Katsuki's ass. Katsuki's hips twitched, searching for more, but Izuku kept his same slow pace, drawing it out. He leaned in, letting his teeth graze over sharp hipbones and up toward hard nipples. A little pull between his teeth made Katsuki whine, and Izuku rewarded him with a slightly quicker thrust, in and out a little rougher. 

"Let me hear you, Kacchan," Izuku demanded. "I want to hear every little noise."

"S'mbarassin'," Katsuki mumbled, tossing his head to the side as he took a gasping breath.

"Show me."

He got a little grumble for his efforts, but slowly his swollen lip was released from its torment, raspy breaths parting those sweet pink lips. 

"How about this?" Izuku asked, tapping the next button on the phone. "Feel better?"

"Yesss," Katsuki hissed, back arching as Izuku fucked him with his toy. "S'good."

"There's my good boy."

Slowly Izuku worked his way up the settings, building it up, until he saw the telltale twitch of Katsuki's cock, the swelling and leaking he'd come to recognise, and quickly he turned the setting down again. 

Katsuki whined indignantly, but Izuku only smiled to himself, slowing his pace a little to keep Katsuki from tipping over the edge. He could keep this up for hours, if he was feeling particularly mean, watching Katsuki tear up and fight for friction, white knuckles tight on the head of the bed to keep from reaching out.

"Let me cum," Katsuki demanded, breathless. "I need to cum."

"Not like that you don't."

Katsuki took a minute to understand, cringing and squeezing his eyes shut tight, the headboard creaking under his grip. He was getting close again, even with the lowered settings, and Izuku slowed his hand to barely a crawl. 

"I need it," he insisted. "P-Please."

"Aww, so polite," Izuku teased. "Getting closer."

He turned the vibrations back up, but this time he made a fist around the base of Katsuki's shaft, holding firm as he fucked Katsuki good and hard with the toy. He could see the vibrations in the way Katsuki's legs trembled every time it went in, could see his pleasure in the way he fought to chase it when Izuku slid it out. 

"Please," he whined, choking on his words. "Please, Master, please, I need to cum so bad, please let me cum."

"There it is," Izuku grinned, timing his last few thrusts of the vibrator with rough, quick strokes up and down his shaft, white fluid spilling immediately over his hand and arm, staining the bedsheets beneath them. "You're so good, Kacchan, so smart."

He eased off with his strokes as the flow stopped, turning the vibrator right down to its lowest setting before he stuffed it back inside Katsuki's asshole. 

"Is that how it feels when you do it yourself?" Izuku grinned.

"God no."

"Lube is your friend, Kacchan. Use it."

"Need a bigger one," he grumbled, turning his head away as his face burned pink.

"Need to stuff your little asshole so full it feels like it's gonna burst?"

"Yeah."

Izuku sat back, leaning against the wall as he waited, letting Katsuki gather himself. He seemed oddly dazed – fucked up, Izuku smirked to himself – but as he began to come to, Izuku saw the gravity of the situation hit him. Saw his eyebrows furrow, the little crease in his forehead becoming more prominent, saw the corners of his mouth turn down.

"Feel okay?" Izuku asked, keeping his voice light. "Doesn't hurt too much, does it?"

"Where the fuck did you learn that shit?"

"Your facial expressions taught me everything I know."

"Fuck you."

"No, you really didn't."

Katsuki scowled, Izuku doing his best not to laugh, a little smirk playing at the corners of his lips still.

"Whatever," Katsuki grumbled, sitting up to wipe cum off his stomach with an old towel. "Your turn, then. What do you want to do?"

Izuku hummed, contemplating, waiting for Katsuki to look right at him, to meet his eyes. "You?"

Katsuki froze, breathing a little faster, and Izuku couldn't resist a grin.

"I know it's, uh, early? We haven't done much yet, really. Like, if you want to wait for a boyfriend or something instead, I get it."

"You want to fuck me?"

"I was getting pretty jealous of your vibe," Izuku smirked, turning the settings up a notch just to draw Katsuki's attention to it. "Think you can do another round for me?"

"Fuck yeah."

Izuku stripped off the last of his clothing, reaching for the lube again and letting Katsuki position himself comfortably. 

"You can move your hands now," he teased, when he saw the hands still tentatively clutching at his pillow. "Aren't you just so well-behaved today? I'm impressed, Kacchan. That's why you're getting a reward, you know. You've been so good for me, I'm gonna fill you up real good."

"Fuck," Katsuki hissed, his cock springing back to life like the fucking traitor it was. "Stick it in me."

"All of this?" Izuku teased, kneeling over him to let his leaking head rub across Katsuki's lips. "You want it in you?"

"Yeah."

"What do you say, then?"

"Fuck you."

"Nuh-uh, try again."

"Fucking please, asshole."

"Oh Kacchan, who do you think can last longer, hmm? The man with his cock on your face, or the needy little bitch grinding against my thigh?"

Katsuki's eyes darted down, hips immediately stilling as he blushed.

"Please," he said again, a little softer. "Please De- Izuku, I want you to fuck me."

"There it is. You're learning so fast. Let's stick with Master though, I don't need to think about this every time my mother says my name."

"No fuckin' way."

"You'll change your mind real quick, and we both know it."

"Asshole."

"Yes, Kacchan, I'm gonna stick it in your asshole, just as long as you keep being a good boy for me."

Katsuki growled quietly, but didn't bother to argue this time, so Izuku lubed himself up and positioned himself between Katsuki's legs, peeking one last time at Katsuki's flushed, needy face, eyes heavy with lust as they watched him.

"Tell me if it hurts, I'll slow down or we'll wait."

"Yeah."

"What's the safe word?"

"Katsudon."

"Good boy."

He slipped the vibrator out, setting it aside on one of the old towels Katsuki had brought out, hitching one of Katsuki's legs up to rest on his shoulder. It gave him a clear view of the twitching hole, still sodden with lube, and Izuku smiled to himself as he slid two fingers inside. Katsuki tensed up immediately, pressing in toward the familiar feeling, searching for the touch he'd come to know so well. Izuku stretched him wide, listening to the little whimpers and gasps that came with his every thrust, and for the first time since their strange arrangement began, he slipped a third finger in.

"More," Katsuki demanded, scowling. "Fucking hurry up, I want it."

"Patience, Kacchan, you need to be ready for it."

"I'm fuckin' ready you've been torturing me since we got here."

"It'll hurt if I do it now."

"I don't care."

Izuku looked down at the flushed, sweaty face, eyes of stubborn frustration meeting his without a hint of shame, and he cracked a smile.

"You want it to hurt, don't you?" he asked. "You've been dreaming of the day your little virgin ass would get torn apart."

"Shut your damn mouth."

"That's it, isn't it? You want to remember this. You want to feel it all night, you want to limp around in the morning and find excuses to not sit down. Don't you?"

"No."

"You want me to flip you over and stuff your face into your pillow while I rail you hard and fast and slap your cute little butt every time you misbehave."

Katsuki hesitated, breath catching, and Izuku smirked. He kept his fingers inside, but leaned down, nipping at Katsuki's neck playfully.

"That's what you want, isn't it? Ass in the air with no control, being fucked to oblivion."

"Yeah."

"Then beg."

Katsuki squeezed his eyes shut, searching every ounce of his being as he debated his moral standards, praying that a tiny piece of him would be stubborn enough to refuse.

As it turns out, Katsuki wasn't as stubborn as people had always claimed.

"Master," he said flatly, keeping his eyes firmly closed. "I want you to take me."

"Oh yeah?" Izuku teased. "How would you like me to take you, Kacchan?"

"From behind, Master. With... With no control."

"There's my good boy."

Katsuki opened his eyes finally, and Izuku made a show of trailing lube onto his shaft, stroking himself to spread it as Katsuki watched hungrily. He hummed to himself as he worked, moaning softly, and against his thigh he felt Katsuki throb.

"Roll over, Kacchan. Be a good little whore and present yourself to me, show me that cute little ass and the gaping hole you want me to fill."

He didn't bother to argue, just rolled onto his stomach and pulled his knees in, sticking his ass up not unlike some of the early fingerings Izuku had given him. That was probably how he knew, Katsuki supposed. Izuku had a way of reading Katsuki like a book; he'd seen how much it made Katsuki pant and moan when his ass was in the air, and he'd filed it away in a more private and intimate version of his stupid hero analysis notebooks.

"This doesn't mean anything," Katsuki insisted, as Izuku rubbed at his hole lightly with the pad of his thumb. "Just because we're gonna fuck doesn't mean... Doesn't mean..."

"It's not gonna turn to more," Izuku smiled faintly. "I know, Kacchan. Sex and love aren't the same thing, and neither of us is dumb enough to conflate the two."

"Yeah," Katsuki mumbled, sighing into the pillow. "It's just sex."

"Exactly. Whoever falls in love first, loses."

Katsuki snorted, but nodded all the same.

"I never lose, nerd."

"I'm not gonna lose this time."

He paused one more time as he lined himself up, glancing at Katsuki's flushed chest, his face hidden in the soft pillow to keep some imaginary ounce of dignity.

"Ready?"

"Yeah, do it."

He pushed the head of his cock through Katsuki's entrance, smiling faintly at the long, low moan it elicited from beneath him. Katsuki was already in heaven and they'd barely even started – his jaw slack, drooling into his pillow, unable to control the noises that came from him.

"Does it feel like you imagined?" Izuku laughed breathlessly, taking his time kneading Katsuki's buttcheeks and stroking his thighs as he sunk in. "Good?"

"So good," he murmured, "so so good."

"Doesn't hurt?"

"Yeah."

"It does?" Izuku asked in alarm, halting immediately. "You should have said!"

"Good hurt," Katsuki explained. "Like... After a workout."

"Tell me if it's too bad, okay?"

"Keep going, it's good."

He slid the rest of the way in, rubbing gently at Katsuki's hip as he moved, and when he was fully seated inside, he fell silent for a moment.

"Now what?"

Katsuki snorted into the pillow, and Izuku cracked a smile of his own, leaning in to lay his cheek against Katsuki's spine.

"What happened to fucking me into oblivion?" Katsuki taunted. "Bit of a change from there to 'now what?' don't you think?"

"Shut up," Izuku laughed. "We're both virgins here, idiot, we're working all of this out together aren't we?"

"Just... In and out, right?" Katsuki suggested. "Like you did with the..."

"Believe it or not, my cock doesn't buzz," Izuku grinned. "But yeah, I'll give it a shot."

He levered himself up again, pulling back until he was around halfway exposed, then gently pushing back in again.

"Yeah," Katsuki nodded, "but faster. Harder."

"It's not gonna hurt?"

"Don't fuckin' care if it does."

"Okay."

He pulled out again, taking a deep breath and gripping at Katsuki's hips, then thrust himself in hard. Katsuki moaned, nodding frantically, and Izuku grinned as he began to pull back again.

"Just like that," Katsuki choked out. "Again. Don't stop."

"Got it."

He picked up the pace, pounding hard and fast between the soft cheeks, and soon he was shifting his body, changing his angle, searching for the place he knew he should be able to find. One little spot; a bundle of nerves, people called it. That one place that would make Katsuki-

"Ah!" he yelped, pressing back into Izuku's grip. "Fuck!"

"Hurt?"

"Fuck no, fucking hit it again right this second you dumb fuck."

"That's not the way we get what we want, Kacchan."

"Fuck!" he whined, searching for movement while Izuku easily held him still. "Master, again! Please grace me with your glorious fuckin' dick or whatever the shit you want to hear! Just do it! Please!"

"You're gonna have to work on that," Izuku laughed, but positioned himself again all the same. "I'm not gonna stop until you jizz all over yourself without even being touched, got it?"

"I can't."

"Tell me that again when I'm nailing your prostate over and over. You can and you will, got it?"

"Y-Yeah," Katsuki whimpered. "Okay."

Katsuki's cock leaked into the sheets, but he did his best to ignore it, keeping his shame beneath him where Izuku wouldn't notice. He could feel it rub against the bed every time Izuku moved, Katsuki's hips shifting with him, but he settled for a shuddering gasp into the pillow rather than admit his desperation.

Then again, Izuku probably knew exactly how desperate he was, but he could at least try to convince himself.

"I'm not gonna stop this time," Izuku said again, running a strong hand up Katsuki's spine in a way that made him shiver. "Once I start, I'm gonna keep going until you cum all over your needy little body. Are you ready?"

"Fuck me into oblivion," Katsuki snorted. "Prove it, asshole."

"That's not how you get what you want, Kacchan. You know what I want from you."

"Fuck off."

"You want me to leave?"

Katsuki's voice caught in his throat, unable to force the snarled words out, so instead he shoved his burning face into his pillow again.

"Answer me," Izuku demanded, grabbing a handful of his hair and pulling him back, smirking at the moan it caused. "You like the hair pulling, huh?"

"Shut up," he hissed. "Just fuck me already, shitnerd."

Katsuki gasped when the hand slammed down on his ass, sending a burning pain across his skin. Again, and he squirmed, but Izuku held him firmly in place as he spanked him for a third time.

"Are you ready to behave now?"

"Fuck you."

"You can behave or I can just jerk off on your back and leave you here in your little puddle of precum while I go back to my room. Then again, you'd probably enjoy that, with the way you moan when I treat you like my little cocksleeve."

"Where the fuck is this coming from?" Katsuki whined. "What happened to the awkward fuckin' nerd I'm used to?"

Izuku smirked, leaning in close, pulling Katsuki's head back a little further to meet his eyes. 

"But you like it, don't you?"

"Shut up."

"Tell me, Kacchan. Tell me how much you like it when I torment you, and I'll fuck you nice and hard."

"I do not."

"No judgment here, Kacchan. What happens in the bedroom stays in the bedroom, remember? No cameras, no recordings, no mentioning it ever again outside of this room. Now tell me."

"Fuck," Katsuki muttered, shoving his burning face into the pillow when Izuku released him. "I like it, okay? I like it when you push me around."

"More."

"It's humiliating," Katsuki mumbled. "And I like it."

"And you're gonna stop denying it at every opportunity?"

"I kind of have to now, don't I, asshole?"

"Yeah," Izuku grinned. "You do."

"Now hurry up and fuck me, Master."

"Well now, how can I resist when you beg so sweetly?"

He pressed on Katsuki's back, pushing him into the mattress, and smirked at the way it tilted his hips like they were just made for Izuku to pound. He finally began to pull out again, sighing with the relief of moving again, and Katsuki whined beneath him as he searched for more motion, more friction, more speed because this damn loser Deku didn't seem to know the meaning of "faster".

Finally, finally, Izuku began to move with vigour. Katsuki didn't bother to stifle his moans, hoping that despite the embarrassment it brought him, the sounds might spur Izuku on. He'd always praised him in the past for being vocal, so maybe, if he was lucky, this time Izuku would give him what he wanted.

"Yes, Kacchan," Izuku panted. "More, Kacchan. Louder."

He turned his head a little, blushing when he heard himself unstifled, but Izuku's nails dug into his hips as he moved harder and faster, and every time he hit that dumb little spot that made Katsuki's knees weak, the embarrassment was worth it.

And he was hitting it a lot.

With a yell he couldn't quite control, Katsuki felt fluid spill beneath him, and Izuku choked out a breathy little laugh as he continued his merciless pace.

"What a good boy, Kacchan. I knew you could do it. Good work, baby."

Katsuki whined, hiding his face again as Izuku came inside him, filling him with heat. He was so full, he couldn't hold it all. It spilled behind him, pooling in the mattress indents around Izuku's knees, and soon the taut figure was rolling over to collapse beside him.

"You can relax, Kacchan," he smiled softly. "Feel good?"

"Fuck yeah. I mean, uh, sure, yeah, it was fine."

Izuku scoffed, and Katsuki cracked a smile as he turned his head to look, eyeing Izuku's sleepy expression with a hint of fondness.

"I should go," Izuku said breathlessly, stroking Katsuki's hair. "You gonna be okay?"

"Uh-huh."

"You did so good," Izuku assured him, pulling his clothes on. "You're such a good... Um, fuck-buddy? That's the kind of term you'd use, right?"

Katsuki snorted, but nodded faintly, running a hand through his hair.

"Yeah, that works."

"I'll see you in the morning."

"Go, nerd. I want to sleep."

"Okay," Izuku nodded reluctantly. "You don't need, um... Like, after-care?"

"For being fucked consensually with no qualms about the matter and occasionally called a whore?" Katsuki snorted. "I'm fine, stupid fuck. Get out of my room already."

"Sweet dreams, Kacchan."

"Yeah, g'night."

Izuku shut the door quietly and padded back to his room, still wondering whether maybe he should have stuck around a little longer. He would text later to check in, a quick thanks and a reminder how good he did. Was that too sappy? Katsuki would probably think so, yeah.

Not that that was gonna stop him.