Work Text:
Everyone has a guilty pleasure. Sirius even has several: he’s never been able to resist caramel, and he can often be heard singing Chappell Roan in the shower. He loves avocados and continues to buy them even though he knows it’s bad for the environment. And at night, he likes to watch his brother sleep.
Caramel is easy to avoid if he just doesn’t buy any; he’s never been the sort to really get embarrassed, so maybe singing Chappell Roan in the shower doesn’t actually qualify as a guilty pleasure. He reckons there are worse things being done to the environment by much richer, more powerful people than him when he buys his avocados. And what hurt can come of only looking at Regulus?
Sirius takes good care of his little brother. He works hard so they have a roof over their heads and always have more than enough food in the fridge, he pays for Regulus’s studies and buys him all the clothes and books he could ever want. He drives him to his therapy sessions, helps him bind his chest whenever Regulus asks, and makes sure he takes his sleeping pills in the evening.
He’s a good brother.
He only ever lets himself give in to his lust when Regulus is asleep, stroking himself as he watches the rise and fall of his sleeping brother’s chest.
Regulus is the picture of youthful beauty like this, his face that of an angel with a smattering of freckles over his high cheekbones, the perfect bow of his pink lips more enticing than any caramel. His dark curls cling to his forehead and with his eyes closed, he looks like a peaceful child resting.
Sirius’s cock is hard just looking at him. He comes closer to the bed, as quietly as he can, and puts his hand down his pants as he studies his little brother’s face. He tries not to moan too loud when his thumb brushes over his slit; he closes his eyes for a moment, not wanting to come too fast.
When he opens his eyes again once his breathing has evened out a bit, Sirius notices Regulus is sweating. He stops his movement and considers the situation.
That cover looks quite heavy. Almost suffocating.
Sirius blinks and takes a tentative step forward, bumping his knees against the bedframe. With his free hand, he lifts the cover off Regulus’s body and shoves it aside, exposing his brother’s pale skin to the low corridor light coming in from the bedroom door he left open. Regulus is only wearing a tank top and a pair of underwear.
The little blood left in Sirius’s brain rushes south at the sight of his baby brother’s smooth, milky skin—his shoulders, his thighs, his stomach where the top slid up slightly. It all makes Sirius’s head spin.
Before he realises what he’s doing, he lets his fingers graze Regulus’s hip. The heat of Regulus’s body burns right through his fingertips, and Sirius has to squeeze his cock harder. He’s covered in precome now, and it only takes a few strokes before his orgasm nearly makes him topple over.
He knows he’s moaning way too loud, but Regulus is still fast asleep.
Sirius’s hand is still hovering over his hip, thumb and index lightly touching his delicate, white skin. With a mesmerised sigh, he lays his palm flat over the side of Regulus’s thigh, half expecting him to wake up—nothing.
It feels magical, so soft and warm. Inviting.
Sirius very slowly, very carefully moves his hand down along Regulus’s thigh, watching for any reaction on his brother’s face, but he’s still perfectly unconscious. Emboldened, Sirius moves back up and gently squeezes Regulus’s ass.
Regulus suddenly moves, turning over. Sirius pulls his hand away in a panic, but Regulus only hums contentedly in his sleep as he shuffles to get resettled in his new position.
That’s enough to draw Sirius back to reality though, and he exits his brother’s room at lightning speed, terrified of what he would do if he let his desires rule him. He can’t stop thinking about it, late that night in his bed and all day long the following day: what would he do if he stopped controlling his urges?
Images of Regulus spread out beneath him, soft and pliant, plague his mind until he’s nothing but a yearning shell of a man, aching all over from what he can’t have.
By dinnertime, the voice of reason telling Sirius it’s wrong is quietened by his heavy breathing, and for the first time, the things he’s always forbidden himself of wanting don’t seem so terrible after all—maybe, just maybe, fulfilling his desires will help him reign them in better. Maybe he just needs to get rid of all the pent up tension in his body from every brush with Regulus’s skin.
Sirius is half mad with love, half crazy with lust when he gives Regulus twice the amount he’s supposed to take to help him sleep.
“I spoke to the doctor about that nightmare you had last week,” the lie rolls right off his tongue. “He told me to up your dose to help.”
“Thanks, Sirius,” Regulus says with such an innocent, trusting smile, and he swallows the pills.
Half an hour later, Sirius slips into his brother’s bedroom.
He starts off softly, making sure that Regulus is fast asleep and won’t wake from Sirius’s caresses. Once the cover is pushed to the side, he lets his hands roam all over his brother’s exposed skin, making goosebumps raise.
Sirius has never felt more excited in his life. He’s buzzing with arousal, in ecstasy from how good every touch feels. He massages Regulus’s thighs for a while, bewitched with the softness of his naked skin under his palms.
A soft noise escapes Regulus, and Sirius freezes.
He looks up, finding Regulus’s eyes still closed, and then the most incredible thing happens.
Regulus shifts to lay on his back and spreads his legs wide open, a clear invitation.
“Sirius,” he mumbles.
“Reg, baby? You awake?” Sirius asks, his mind going a mile a minute.
Regulus doesn’t reply, but he thrusts into the air and gives a frustrated moan. Sirius can’t deny him.
He moves his hands to press over Regulus’s underwear, and the most delightful whimper falls from Regulus’s lips. He wants this. Regulus wants him.
Sirius doesn’t need more to slip his fingers under the damp fabric. He and Regulus moan at the same time when he presses over his cunt, teasing his clitoris until he’s soaking wet and his fingers slip right inside.
He pulls the underwear down with his other hand, then replaces his fingers with his tongue.
Regulus tastes better than he could have ever imagined. That and his scent alone are making Sirius high, and he has to fight not to take his leaking cock in his fist. He wants to savour this. Regulus squirms under him as he licks him, sucking on his clitoris and pushing his tongue as far as he can inside of him, lapping up every last drop he can get.
“Please, Sirius, fuck me…”
Sirius pulls away to look at his brother’s now open, pale grey eyes. His look is hazy, his pupils blown, and it’s unclear whether or not he’s conscious—but it’s clear enough that he wants this.
“You sure?” Sirius still asks.
“Yes, I want…”
“You want to feel me inside you?”
“God, yes… Please, fill me up, Sirius…” He’s slurring slightly, which only adds to how alluring he is right now, begging for Sirius’s dick which is still painfully untouched.
“Alright, baby boy.” Sirius moves up his body and kisses him on the mouth, making him taste himself on Sirius’s tongue. Regulus kisses him back sloppily, and soon both their chins are wet from the mix of arousal and spit.
“Please, fuck me…” Regulus whimpers again, pushing his hips up into the air once more.
So Sirius obliges. He gets rid of his clothes and lines up carefully, stroking Regulus’s oversensitive cunt with his head before pushing in slowly.
“Oh, god, Sirius…”
Regulus feels so warm and wet around him, so perfectly tight, Sirius has to focus to stop himself from trying to breed him like a fucking dog.
“Alright, baby?” he asks, voice low.
“Sirius… Sirius…” is all Regulus says.
Sirius pulls out, muscles strained in effort and paying attention to every little sensation. His nerves are on fire, making each movement, each touch, each friction that much more delicious. He feels like he’s in heaven. The pleasure is all encompassing, pressing around him from everywhere, and soon he can’t stop himself from slamming down again.
Regulus moans loudly, and Sirius does it again, a little faster. He gets pulled by the back of his neck into a searing kiss, moving his hips languidly as Regulus sucks on his tongue and pulls his lips between his teeth. His hands move to Regulus’s small breasts, teasing his nipples one after the other, enjoying the soft flesh under his hands.
“Sirius, please, faster,” Regulus grunts. “Harder.”
It doesn’t take long before Sirius stops restraining himself at all, instead thrusting hard and fast into his little brother, close to losing his mind from the tight warmth of his cunt.
“Fuck, you feel so good,” he chokes out. “So perfect, so tight. Like you were made for me, weren’t you, baby?”
“Yes. Fuck, yes, Sirius...”
“God, you’re taking it so well. You’re such a good boy. Such a good boy for me.”
“Fuck, Sirius…”
When Sirius lowers one of his hands to circle Regulus’s clitoris with his thumb, Regulus’s thighs start to shake, and he makes the most beautifully obscene moan. Sirius feels him clench around him, and he accelerates again, chasing his own high as Regulus comes apart under him.
It only takes a few more thrusts before Sirius is coming too, releasing deep inside his brother.
Both of them are sweaty, shaking messes, and Regulus wraps his arms and legs around Sirius to keep him there while they catch their breath, forehead to forehead. Sirius dips down for a kiss, and Regulus lets out a giggle against his mouth.
“You’re inside of me,” he says.
“I sure am. Is that okay?”
“More than okay.” Regulus gives the most adorable little self satisfied nod. “Feels so good. So full.”
“So you liked it?” Sirius asks, starting to regain some of his thinking abilities.
“I loved it,” Regulus assures him through a yawn. “We’ll have to do it again when I’m not high on sleeping pills, though.”
Sirius can’t help a snort. “Sorry.”
“S’okay. I woke up in time to enjoy it. But next time,” Regulus says, interrupted by another yawn, “I’d like to be there for the whole ride.”
He looks into Sirius’s eyes fiercely, with the cutest determined face Sirius has ever seen. He gives him a quick kiss and says, “You’ve got yourself a deal.”