Like A Time Bomb Set Into Motion

Pairing: Harry/Louis
Rating: NC-17
Words: ~4,000
Summary: Harry is 19 years old, Louis is 11, and they’re brothers. Harry’s not sure their mom was thinking of sex when she told Harry to watch his younger brother, but, well, he told Louis not to touch his stuff.

A/N: written for this prompt. this might not have been exactly what the prompter wanted, but please, tell me what you guys think! x

read on ao3 here

Harry’s relaxing on his bed, leaning against the headboard casually and flipping through a magazine, when a small body comes barreling through his door. Harry sets his magazine aside as the little bundle of energy jumps onto the bed and flops down next to Harry. Harry smiles fondly down at the boy, his 11-year-old brother Louis.

"Hey, Louis, what are you up to?" He asks, voice sweet.

Louis rolls over so that he’s on his back, head balanced on the edge of the bed, arms dropped over and hanging from the side of the bed, too short to reach the floor.

His whole body is practically vibrating with excitement, a near-constant emotion for the young boy.

"Wanted to see you!" Louis announces, wiggling around some more so that he’s now back on his stomach and facing towards Harry.

The light from the window Harry has next to his bed is hitting Louis just right, turning his hair from brown to golden and lighting up his whole face and Harry’s stomach churns guiltily as he thinks about how pretty Louis is. He’s had these thoughts before - some worse than others, like when Louis’ wearing those tights trousers he likes and he bends over and Harry has to remind himself over and over again that this is his brother and he’s 8 years younger than him.

The thoughts still come to him, thoughts of how much he’d like to kiss Louis on his pretty pouty mouth, of how much he wants to squeeze those thighs, of how little Louis is and how delectable his arse is and a long list of things a 19-year-old boy shouldn’t be thinking about his much younger brother. He feels guilty, of course he does. That doesn’t stop Harry at night, though, from coming into his own fist with a soft cry, trying to keep quiet, Louis’ name at the tip of his tongue.

Harry’s gaze travels up and down Louis’ body shamelessly, until he notices Louis’ confused expression and stops.

"Uh, cool." Harry replies, realizing he hadn’t yet.

Louis’ brow furrows and his bottom lips curl into an exaggerated pout.  

 ”Is something wrong, Haz?” Louis asks, and Harry’s stomach flutters at the nickname, sounding adorable coming from Louis’ mouth. 

Harry shakes his head, smiling. “No, Boo, I’m fine.”

Louis looks like he wants to say something else, but his eye catches something on the ground next to the bed.

"What’s that?" Louis asks, pointing at the box he found.

Harry gulps. Oh shit. That is not an appropriate box for a 12-year-old to open. He could’ve sworn he had that tucked underneath his bed and not out in plain view. It’s a regular shoe box, nothing conspicuous, but its contents are not something he wants anyone seeing. 

“Oh, it’s, uh,” Harry stammers, trying to think of an excuse. “It’s just an old shoebox, nothing interesting.”

 Louis crawls over to the side of the bed and looks at it, head cocked.

“It looks full, though,” Louis observes, and yeah, you can kind of tell that there’s stuff in it.

“Just drop it, Lou.” Harry says, voice maybe a little harsher than necessary.

Louis looks upset, but he still has that curious twinkle in his eye, so Harry bends over and pushes the box under his bed, before turning towards Louis.

“Listen to me, Louis. Don’t ever look in that box.” He orders, looking Louis straight in the eye, trying to get him to listen. “Do you understand?”

Louis nods, and Harry really hopes that he didn’t just make Louis even more curious. Oh, well. Louis’ rarely in his room alone. Well, not that Harry knows of.

They chat for a bit, and then somehow Harry ends up on top of Louis, hands running up and down the younger boy’s body, tickling him fiercely. Louis is shrieking with laughter, wiggling around in a desperate attempt to get away from Harry’s grasp. They’re interrupted when their mother calls Harry down.

“Harry!” She shouts up the staircase. “Come down, honey, I have to talk to you!”

Harry climbs off of Louis, who looks disappointed and makes grabby hands at Harry, trying to get him to come back.

“I’ll be right back, Lou.” Harry assures his younger brother. “Stay right here.”

He trots down the stairs and nearly runs his mother over as he slides around a corner and into their kitchen, where he knows she is.

“Hey, Mum, what’s up?” Harry asks, watching as his mum flits around the kitchen, looking through cupboards and the fridge and writing what they’re missing on a list.

His mum looks up at Harry and smiles.

“Your father and I are going shopping and then we might go for dinner together, so could you please look after Louis in the meantime?” She asks, eyes pleading. “He’s a bit excitable today, you know how he gets, so if you could just watch him and then cook up some Mac ‘n’ Cheese or something, that would be wonderful, Harry.”

Harry nods, smiling right back at her. He didn’t have plans today anyways, and he loves his little brother, really, so it’s not a problem. “Yeah, sure, I can do that, Mum. We’ll be fine. You have fun.”

His mum looks extremely grateful. “Thank you so much, Harry!” She says, then looks at her watch. “We’re going to head out, now. Lou loves hanging out with you so much, he probably won’t even notice we’re gone.”

Harry laughs, and waves as his mum leaves, oversized purse in hand and repeating ‘thank you’s to him.

Once she’s gone, Harry makes his way back up the stairs, delighted at the prospect of spending a lazy evening with his brother.

 “Guess what, Lou? Mum’s gone out so if you’re extra good we can have Mac ’n’ cheese for dinner!” Harry says, swinging the door to his room open as he speaks.

He stops right in his tracks as he sees what Louis’ up to. The boy mirrors his movements, freezing his actions as well, looking up at Harry guiltily. In front of Louis, on the bed, is Harry’s shoe box – the very one Harry had strictly ordered Louis not to touch – opened up and displaying its contents.

“I’m sorry!” Louis whimpers right away, pulling his hands away from the box quickly, as if he were touching something hot. “I was curious! I didn’t – I just wanted to know!”

Harry’s eyes widen and he stomps over to the bed, roughly wrenching the box out of Louis’ grasp.

“I told you not to open this!” Harry shouts, angry and embarrassed.

Louis bows his head, ashamed and maybe just a little bit scared of his brother right now.

“Look at me when I’m speaking to you!” Harry growls, grabbing onto Louis’ chin and forcing him to look up.

Tears are prickling at the corner of Louis’ eyes and he looks extremely guilty.

“Please, I’m sorry Harry! I swear I didn’t mean to make you mad!” Louis says, voice pleading. “And – and if what’s in there is supposed to be a secret… it’s okay, because – because I don’t even know what those things in there are! So it’s okay! Right?”

"No, it’s not okay, because I told you not to do something and you did it anyways!" Harry yells, and then takes a few deep breaths, calming himself down. He thinks for a moment, remembering Louis’ words.

"You don’t know what these things are, huh?" He asks, and Louis shakes his head, looking hopeful that Harry is going to let him off the hook.

Harry reaches into the box and pulls out a pair of handcuffs. The box is full of other things - sex toys, mostly - that he uses on himself. The handcuffs were a gag gift from one of his mates, and he ended up throwing it in the box with the rest of his things.

He’s never used them before. He’d only had sex twice - once with a girl and once with a boy, and both times they’d been at the other person’s house. It’s kind of hard to get it on in a bedroom next to your parents’ and your younger brother’s bedrooms. 

"Do you know what these are?" Harry asks, holding up the handcuffs.

Louis hesitates, and then nods. “They’re - handcuffs?” Louis answers tentatively. “Like the police have. Why do you have them?”

"They’re not just for police," Harry explains, smirking. "They’re for anyone who has to enforce a law. They’re a punishment."

Louis nods, even though he’s confused as to what point Harry’s getting at.

"You know who gets punished, Louis? Naughty boys. And who has been a naughty boy, today, huh Louis?" Harry asks.

"I have," Louis replies, voice small and shy, unlike the boy’s usual demeanor.

"That’s right, baby." Harry purrs. "So I’m going to have to use these on you, aren’t I?"

Louis’ eyes widen and he looks at the handcuffs, terrified.

"What - what are you gonna do?" Louis asks.

"You’ll see. Now don’t give me those surprised eyes. You were a bad boy, and now it’s time for your punishment." Harry reprimands, setting the box aside, the key to the cuffs in it, handcuffs still in hand.

He knows this is wrong, but he’s pissed off, and their parents are away, and Louis’ face is flushed with embarrassment and Harry is so turned on by it.

"Turn around and face towards my pillows," Harry orders, voice dark and low with lust.  

Louis complies easily, shaking slightly with fear and anticipation. His brother has never spoken to him like this. 

"I’m going to tie you up and you’re not going to say a fucking word." Harry says, trying to keep his voice even.

Louis winces, but nods - he doesn’t want to argue when Harry’s like this. He’s never heard Harry say one explicit word in his life - not to him, at least.

The headboard of the bed consists of one horizontal bar with several vertical bars attached to it. Harry clamps one cuff onto one of Louis’ wrists, then threads the other cuff through one of the vertical bars near the center and locks it on Louis’ other wrist. The handcuffs are fuzzy and an obnoxious cheetah print, so they shouldn’t hurt Louis too much, but Harry checks Louis’ face anyways. He doesn’t seem like he’s in any pain. Not yet, at least.

Louis squirms, trying to get into a comfortable position. Harry helps him out by putting a pillow under Louis’ chest for him to rest on, propping the boy up. The sight Harry has in front of him is exquisite - Louis, elbows splayed out with his wrists bound above him, chest and head down, arse up and breathing heavily - making him lick his lips. Harry is way too aroused to feel a shred of guilt anymore.

Harry doesn’t waste any more time and crawls over to Louis, and pulls down both his trousers and his pants, staring at the pert little arse that meets his eyes. Louis squawks in surprise and shuffles around even more, his neck craning to the side as he tries to look at what Harry’s doing.

"Now, Louis, I’m going to teach you one simple lesson." Harry says, and then smacks Louis right on his arse.

Louis cries out in pain, and Harry watches as the boy’s arse cheeks jiggle and turn an adorable shade of pink.

"Don’t," Harry continues. "Touch. My. Stuff."

He accentuates each word with a slap to Louis’ arse, the ‘smack!’s ringing clearly through the room. Louis’ cries turn into whimpers of pain and the noise sends electrifying jolts to Harry’s cock. He’s now hard in his trousers, and he has to resist the urge to pull his own trousers down and wank himself off right onto Louis’ arse. He didn’t know how much spanking his younger brother could affect him.

"Please - stop, Harry! It - it hurts!" Louis begs, trying to sit down on his legs to cover his exposed arse, but fails because his wrists are bound too high up.

"Hm," Harry says, pretending to think. "Have you learned your lesson?"

Louis nods frantically, looking back at Harry with panicked eyes. “Y-yes! I swear! I w-won’t ever do it again!”

"See, now I don’t know whether or not to believe you," Harry muses. "You told me you wouldn’t touch that box, but you did. I still think you deserve a bit more punishing, until you’re sincere about your apology.”

"I am!" Louis cries, in an attempt to convince Harry, but he’s not having it.

Instead, Harry relentlessly brings his hand down on Louis’ arse another five times, the motions rhythmic, and the skin on Louis’ arse cheeks turning a brilliant red.

Don’t lie to me." Harry hisses as he spanks Louis.

Louis’ head is now lolled against the pillow, his face turned back towards Harry. Tears are streaming down the young boy’s face and, well - now Harry feels a bit guilty. This is his brother, after all.

He frowns sympathetically, and goes to retrieve the key from the box when he catches Louis rutting up against the pillow his chest was resting on, face scrunched up. Harry furrows his brow, confused.

"What are you doing, baby?" He asks, resting his hand on the boy’s back gently.

"Hu-urts," Louis hiccups, eyes opening slightly to look at his older brother.

"I know, I’m sorry, that was…too much. I know you didn’t mean to make me mad." Harry says, voice soft, trying to soothe Louis.

Louis shakes his head though. 

"It’s n-not that..I f-feel funny…" Louis whimpers, and then shifts his hips and - oh.

Hesitantly, Harry snakes a hand experimentally in between Louis’ body and the pillow he’s propped up on. Louis’ eyes widen and he squeaks as his brother’s hand skirts down his body and comes to rest on his crotch.

"Here?" Harry croaks.

"Y-yeah," Louis pants, and then, because he can’t help himself, pushes his hips up into Harry’s hand, trying to find some friction to relieve the odd pain he’s feeling. "D-down there. It’s…h-hard. It hurts."

Harry takes a few deep breaths, trying to calm himself down and keep himself from coming right in his pants because holy fuck, Louis is hard from being spanked. He made his 11-year-old brother hard.

"I - I can take care of that," Harry says, voice a bit strangled. He gulps, and then clears his throat, before continuing. "If..if you want me to. I can fix that."

Louis nods as soon as he hears the words come out of Harry’s mouth.

"Please, Harry, it hurts!" Louis whines, his hips pivoting and grinding against the pillow.

"Okay, baby, hang on," Harry says, and then reaches over to grab a bottle of lube and a condom from the drawer of his bedside table.

He can’t believe he’s about to do this.

"Do you know what getting hard means, Louis?" Harry asks politely.

"I - I’ve heard people talk about it before…" Louis admits, voice quiet. "Boys at school."

"Well then you must know how naughty it is. How dirty.” 

Louis shakes his head. “I didn’t know! I’m sorry. I c-can’t help it!”

Louis looks so guilty that Harry decides to relent and forget the whole punishment. He’s not going to stop his plans, though, and he’s certainly not going to unbind Louis - his handcuffed state is way too much of a turn-on.

"Shh, it’s okay, baby. Wanna know a secret?" He whispers. "I’m hard too.”

"Y-you are?" Louis asks, curious, and sounding a little bit less ashamed of himself.

"Yeah, so I’m going to take care of both of us. How does that sound?” 

Louis replies with a quiet ‘good’, and Harry smiles. 

Then, he lubes up his fingers, slicking on a generous amount so that Louis experiences as little pain as possible. He was angry at Louis, before, but he knows how much it hurts to be fucked with too little preparation – he’s experienced it – and he’s never want to wish that open his baby brother. Carefully, he spreads Louis’ arse cheeks apart, and brings up one of his fingers to the rim of Louis’, circling his entrance with feather-light touches. Louis gasps at that, but seems to like it, pushing his arse back.

"Okay, babe, this might feel a bit weird. It gets better, though." Harry promises, before plunging one slippery finger into Louis.

Louis lets out a cry of surprise at that, but then is quiet. He looks a bit uncomfortable, but not like he’s in pain, so Harry starts moving his finger in and out of Louis’ hole, scraping against the velvety walls. All Harry can feel is tight heat, and he’s so impossibly hard, but he has to prepare Louis as best as he can.

"How are you doing, bud?" Harry asks gently.

“‘S weird.” Is all Louis says, and yeah, Harry knows what he means. It’s weird the first time.

"It gets better." Harry assures him again, and then crooks his finger at just the right angle, and Louis cries out, this time in pleasure.

"D-do that again," Louis pleads, panting heavily. "Felt so good."

So Harry does. He curls his one finger in that one spot, over and over, until Louis is pushing back against him and begging for more. Harry complies, and slips a second finger alongside the first.

He gives Louis a few moments to adjust. He’s incredibly tight, and Harry doesn’t want to hurt him any amount, considering the off-chance Louis might ask him to stop.

Eventually, Harry starts scissoring his fingers, stretching Louis’ walls apart as gingerly as he can. Louis’ face contorts into a painful expression for a moment, but it passes when Harry slowly pushes his fingers deeper and hits that sweet spot of nerves, being replaced by a dazed look of pleasure.

Harry starts thrusting his fingers in and out once again, and it’s shorter this time before Louis is asking for more.

Harry complies again, tucking a third finger into Louis’ tight hole. He gives Louis a bit of time again before he starts moving the fingers. Once Harry’s stretched Louis out with three of his fingers, he pulls them out, wiping them on the sheets, and reaches for the bottle of lube again, grabbing the aluminum packet of the condom as well. Louis makes a noise of complaint, but Harry shushes him quickly.

“Hang on, you’re gonna like this. Just be patient.” Harry promises,

Harry, still fully dressed up to that point, quickly strips himself of his trousers and his boxers. He leaves his shirt on, though, because Louis has his on still and, well, he’s kind of in a rush. He’s painfully hard from fingering Louis open, even harder than before, and he wants nothing more than to fuck his brother’s tight little arse.

He rips open the condom package frantically and then rolls the rubber onto his dick, hands shaking. Messily, he pours lube onto his palm, and then rubs it onto his hard-on, making sure to thoroughly slick up his cock to reduce the pain Louis will have to go through. When he’s done, he places his hands on either side of Louis and props himself up there, his chest to Louis’ back.

Louis doesn’t say anything, just waits for Harry to do something. He’s tense, though. 

"Baby, you gotta relax, or this might hurt." Harry whispers into Louis’ hair, who immediately loosens up, eager to please his older brother. "Good boy."

Harry puts all his weight on one hand as he uses the other to guide his dick to Louis’ arse, prodding the head of his erection up against the younger boy’s entrance. Louis squeaks in surprise, but is otherwise silent.

Harry places his hand back down and slowly, very slowly, he pushes his hips forward, sliding the head of his cock past the rim of Louis’ hole.

Louis cries out, and Harry stills his movements.

"Do you want me to stop?" He asks quickly, checking Louis’ face for any sign of discomfort. The boy looks like he’s in pain.

Louis nods his head, and Harry moves to pull the tip of his cock out, but then the other boy seems to change his mind and shakes his head instead.

"Alright, baby, I’m going to go slowly. I just need you to relax, okay? It might sting a little bit, but I promise if you relax and wait it will feel good." Harry explains, voice soft.

Harry gets a look at Louis’ face and sees that there are fresh tears in his eyes, but Louis nods his head anyways. 

That’s enough for Harry, who continues to push his cock in, ever so slowly, not stopping until he bottoms out. Louis is making these quiet little pained noises, and Harry knows he’s hurting the younger boy.

"Harry, please," Louis whispers, voice barely audible. "Please stop. It’s too much."

Harry’s too far gone, though. Louis’ so, so tight and so, so hot around him, and there’s no way he’s pulling out now.

 Instead, he pecks Louis on the head and says, “Baby, just wait a little bit, I promise it gets good.”

Louis accepts that, and tries his best to relax his muscles as his older brother looms over him.

Eventually, Louis’ pained expression dissipates, and Harry takes that as the go ahead to start moving. Slowly at first, Harry pulls his hips back and then thrusts his cock back into Louis’, the friction intense. Louis lets out a strangled scream, but cuts it off by biting down on his lip, not wanting to anger his brother.

Harry stills for a bit, before thrusting back in and out. Louis seems a bit more comfortable now, and actually seems to be enjoying himself. When the younger boy starts bucking his hips backwards as much as he can manage to meet Harry’s thrusts, meanwhile letting out little “uh, uh, uh”s, Harry knows he’s feeling the pleasure now.

"That feel good, baby?" Harry asks, raising his hips to slam back down at an angle that will hit Louis’ prostate as best as he can manage.

Louis cries out a, “yes!” and Harry smirks, speeding his thrusts up.

Louis’ shaking now, his thighs quivering and his arms moving around clumsily, and his whole body is flushed a delightful red, and it’s so, so hot. It’s so, so good – all Harry has to do is not think about the fact that he’s taking his little brother’s virginity. His 11-year-old brother.

"Harry, stop! I’m gonna - I feel like I’m gonna pee!" Louis shrieks, and Harry can tell he’s about to climax.

Louis’ whole body shudders as he comes, a high cry escaping from his throat, and then he’s spent. He collapses on the pillow, arms still strung up and head lolled to the side, exhausted from the exertion.

Harry keeps up his thrusts, though, feeling as Louis’ walls tighten around his cock. It’s too much for Harry, who comes at the feeling, still inside of Louis. He thrusts through his orgasm, riding out his high, while Louis just lies there and takes it. 

When he’s calmed down enough and his breathing is even, Harry pulls out, slipping off the condom, tying it, and tossing it into the waste-bin beside his bed. 

He unlocks Louis’ handcuffs then, and coaxes him into rolling over so that he can clean him up. Gently, he grabs a tissue and wipes the small amount of come from Louis’ stomach, before slipping the soiled pillowcase off his pillow, balling it up, and throwing it to the end of his bed to deal with later.

Louis curls up into Harry’s side, nuzzling his older brother’s neck with his face affectionately. He looks fucked out, his hair sweaty and sticking to his forehead and his eyes glazed over.

"You can’t tell anyone about this, okay?" Harry whispers, suddenly remembering the fact that oh yeah, this is his brother.

He doesn’t feel guilty, though. Louis looks too happy for him to feel bad about this.

"Okay," Louis agrees. "Can I have that Mac ‘n’ Cheese now, though?"

posted 1 year ago with 269 notes
#larry smut
#larrystylinsmut
#larry fanfiction
#larry oneshot
#larry stylinson
#os
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