Chapter Text
Sirius had no idea how to feel about this. His brother was standing there, looking damn hot, and he just couldn't ignore it.
He had, he had tried. He had looked away whenever he caught himself looking too far.
He had pretended not to see his brother's advances, and he had walked away from him when things got complicated because Regulus seemed determined to get something that was forbidden.
That didn't make him a coward. Or so he kept telling himself. Still, Regulus was still there, insisting on something that for the first time Sirius couldn't give him. Because he loved his brother more than himself. But that was too sacred a line.
It was all he had criticized Walburga for, beyond the literal torture she had put them through.
Sirius would be lying if he said he'd never seen him that way. Honestly, Sirius had become hyper-aware of his brother about a year before Regulus had lost his mind and told Sirius to fuck off, in his room at Grimmauld Place the day before he was due to return to Hogwarts for Sirius's 6th year. "I don't understand why the fuck you care so much. It's in our fucking genes, for Merlin's sake," he'd said, and for a moment, Sirius seriously considered giving in. Just giving in to his brother. The tension had been there for a long time, after all. And Sirius didn't think he could stand it much longer. But he couldn't. He started avoiding him publicly after that.
The voice in the back of his mind kept eating away at him.
Even with his breathing so close, even when his brother was there, calling him a coward. The voice of his conscience was still there, insisting that this was his little brother, and he couldn't just pretend it wasn't.
He had tried to walk away, listening to that voice. He had, and it ended up much worse than they were before. It brought them here, because Sirius had followed Regulus around the castle after he stormed out of the party they were at, because Sirius had gotten too close to a girl he couldn't even remember the name of.
He selfishly thought that if he gave him space, _it_ would just go away.
It didn't.
"Tell me to my face that I'm a sick bastard who's alone in this." His brother said spitefully, and Sirius could cry from the anguish the situation brings him.
"Reg I don't-" his brother snorts with a hatred that is very unlike him. The boy he knows. Sirius hates himself a little for doing that to him. "You know what? Forget it." Regulus makes a move that upsets Sirius. He knows he's about to leave. He knows Regulus stopped fighting, and he hates it because deep down he wanted this too.
Then he stops him, in a fit of idiocy, which doesn't even matter anymore because, honestly, his brother is there, millimeters away from him, and his hot breath consumes him along with the smell of firewhiskey emanating from him. Not counting the boy's own smell, which is hard for Sirius to explain, but if he had to put it into words he would say it smells heavenly.
He sighs, and then makes a decision. One that he knows will send everything to hell. But, honestly? He doesn't care. To hell with the world too if he wants, Sirius is going to be selfish for the first time in his life. And you know what? He's going to enjoy it.
It only took Regulus a couple of months to accept this, as far as Sirius knows. And Sirius would know. He just cursed under his breath, looked at the family history, and sent everything to hell, because, that was Sirius, his older brother, the boy who took care of Regulus when he himself was a child too. Sirius knows that line of thinking intimately, because his brother isn't too different from himself. Which is as terrifying as it is narcissistic. As damn hot as it is.
Fuck Barty and Evan too, now that Sirius thinks about it. Because he'd bet his wand that they helped Regulus just accept the fact that he had a crush on his own brother. He could swear the morons just joked about his lineage to get over it.
Not that he'd let it go. Sirius has a sneaking suspicion that, in fact, the main reason Regulus spoke to his face and told him straight up how he felt had a lot to do with his friends.
Sirius knows, for a fact, that none of his own friends are going to judge him. They might be a little alarmed. They'll lose their minds, understandably. But Sirius knows they'll get over it. They always do. They have to.
So he just does it, closes the small space between him and Regulus, and brings their lips together.
Their lips slowly collide, and Sirius's mind understands. It just fits. Because all this time all he had to have done was this. Not wasting his time pretending false morals that he didn't have. He didn't have to have them. He was a Black.
All he had to do was kiss his brother in Grimmauld Place, under the dark and gloomy atmosphere of the place, and under the stars that name them, the day Regulus faced him.
All he had to do was kiss him now, slow, and sweet, and like it should have been from the start. Here, in this abandoned hallway in the middle of the castle.
###
"Look me in the fucking face, Sirius Orion Black, and tell me you don't feel the same way." _tell me your gaze doesn't magically travel to me no matter how many people are here._
Regulus had Sirius cornered, demanding the truth he already knew. He was sick of this. Of pretending it wasn't happening.
"I don't know what you're talking about, Reggie."
And there it was again. Reg hates him. He hates Sirius, and his stupid nicknames, and how he makes him feel. And he hates above all else that Sirius kept pretending he wasn't aware of everything he does to him.
"Fuck off. Honestly."
And he didn't want to do it, he really didn't, but Regulus decided that Sirius had to decide this. If something was going to happen, it would be because Sirius decided it. Reg already made his point, following Barty's advice against all better judgment, and he knew his brother felt the same. He knew him well enough to know. For the casual touches of his hands that made him shiver, for the way he looked at him as if he were something worthy of veneration
They are there, in the middle of an abandoned Hogwarts hallway, after a party in the Ravenclaw common room, with Regulus blocking Sirius's exit, after he caught him following him. Searching for an answer that is obvious enough to know for itself.
Sirius looked upset. He seemed to want to run away from there. Reg is aware that he would, if he had the chance. It gave him a slight deja vu.
"You always run away. Like a fucking coward. First from home, then from me. Stop pretending you don't know, Sirius. Stop it. And if I'm just imagining things, tell me. Tell me to my face that I'm a sicko who's alone in this."
"Regulus, I don't-"
Reg sneered. "Forget it." He turned around, intent on getting out of there. He was dizzy from the alcohol, and a little too frustrated with his stupid brother. Sirius would be a jerk no matter how many times Regulus confronted him. No matter how obvious it became each day. The way Regulus noticed just a second ago that his brother's gaze was on his lips.
But Sirius was Sirius, and that wasn't going to change just because. Except.
Except because Sirius stopped him. He took him by the arm, and stood in front of him, blank.
Regulus knows that was one of his stupid Gryffindor impulses. He knows it. Because that's Sirius, and that's how he acts. He doesn't let him get close, but he doesn't let him go either. But he knows it because even though Sirius's gaze is determined, he hasn't said a single word.
Regulus rolls his eyes after three seconds of silence. A record for his brother, if you ask him.
But as he's about to pull away, Sirius tightens his grip and pulls him even closer.
Regulus is now hyper-aware of Sirius's labored breathing, as well as the alcohol on his breath. He has to look up to meet Sirius's eyes, which irritates him. Their lips are millimeters away, but Regulus can't look away from Sirius's eyes. So fucking familiar, and with a spark Regulus doesn't think he's seen in decades, when they were still kids, and Sirius first challenged Walburga. It was a spark of madness, that was it. But Regulus wasn't going to push Sirius any further. He'd already dragged him this far. His brother had to make the decisions now, and Regulus couldn't hate himself more for this, but that's how it was.
And then Sirius closes the distance between them, and Regulus could cry with happiness.
The touch starts soft, and slow, and Regulus knows this is for Sirius. Because he needs time, time to accept this, time to not freak out and run away.
Until Sirius seems to have a revelation, and now he launches himself straight at his brother, crashing not only their bodies into a wall in the process, but deepening the kiss.
And Regulus' mind just blurs. His existence is reduced to his own brother's lips and tongue making a mess of him.
His mouth tasted like Firewhiskey. And he'd be lying if he said that didn't factor into Sirius' epiphany. But honestly? He's making out with his own fucking brother. It's an accomplishment in itself. Fuck him if he's going to be blamed for using alcohol as a catalyst.
Sirius bites his bottom lip, and Regulus feels himself moan into his brother's mouth. He doesn't even care. He's waited for this long enough to lose his embarrassment.
Sirius pulls away with a smirk, and Regulus wants to wipe it away so badly.
The distance between them is still short, and the dangerous glint hasn't faded from his brother's eyes. But it's not just that, there's something. Something else, that wasn't there before, and Regulus can't quite put it into words. But it's there, and it's driving him crazy because, honestly, he might just moan under Sirius's sinful gaze again.
Not that he's going to waste it. Regulus runs a hand through his brother's locks of hair, and lightly digs his nails into his scalp.
Sirius's smile fades, to Regulus' absolute delight, leaving something more primal there. And then it's back, with the force of a hurricane, back in his mouth.
Sirius runs his tongue against his bottom lip, and Regulus thinks he's going to die the moment he feels his brother put his hands on him.
It's shallow, and shy, which is surprising because that's Sirius Promiscuous Black, but it's there, soft at his waist, not going too far, just a touch.
And then he sends everything to hell once again, because he's gone far enough, and if Sirius is going to stop anything, it's going to be now. Because Regulus thinks that now that he knows how his brother feels, he's not going to let him go ever again. He has no intention of doing so.
So he tests him. He pulls Sirius by his hair, closer to him, as if that were physically possible, and subtly spreads his legs a little, so that he's properly cornered against the wall.
Sirius is a jerk, but he's not stupid. He doesn't waste a second in placing his knee between his legs, and now it's Regulus who pulls away, with a smug grin, because he tricked his brother to get exactly what he wanted.
Sirius noticed. Regulus knows, and it's the reason he did this in the first place. Maybe it's because of too much bravery, because of the firewhiskey, maybe because the Gryffindor ways were passed on to him from Sirius through the kiss, or maybe because he just has nothing left to lose. But he does it, he's teasing Sirius on purpose.
His brother's eyes have always been so expressive. Too much. Normally it was a problem, but now... Regulus sees it. He sees the resolve in his surprised eyes, and he sees that he made a mistake the moment his eyes darken. And you know what? It's exactly what he wanted.
Sirius moves down to his neck, and runs his tongue slowly, teasing him.
Regulus is going to go crazy. He throws his head to the side, and lets himself be lost in Sirius's ministrations because honestly? he'd be lying if he said he wasn't good at what he does. Which makes him angry and excited in equal parts, because he hates that Sirius knows all this stuff, because it means he did it with someone else. But also, his mind can't wander too far in that direction, because Sirius just bit his collarbone, and all Regulus can do is concentrate on biting his lip so he doesn't scream, or moan.
Sirius notices, because of course he does. Then he moves back up, and speaks into his ear, letting his breath out before he speaks, and as if he wasn't driving Regulus crazy enough right now, his voice is hoarse, and low, and he could come just from listening to it.
"Come on, Reggie. Don't make me beg to listen to you, okay?"
He couldn't hold back the moan that followed that. And the thing is, he doesn't even want to obey Sirius. He is, despite everything before, his brother, and the rivalry isn't going to go away because of this. And first of all, even if he is a fucking incestuous man like his family, who must be turning in their graves right now, albeit for different reasons than they should, Regulus knows that. He's still Regulus Black, and he still has pride to uphold. Or at least he can still bring Sirius's fucking ego down. And oh, it would be so much easier if the git wasn't so damn good at what he does.
So he tugs on Sirius's hair again, which now that he looks at it better, leads him to a discovery. Sirius wasn't expecting that, and he couldn't help the gasp that left his lips. Which makes Regulus less miserable because while his brother is bringing him down lower than he should, he's not sinking alone.
But this is a game of pride, and Regulus has already given Sirius enough of an advantage.
So he pulls him to his lips, at the same time lifting his hip against his knee, because he knows it's going to drive his brother crazy. Sure, it also rips a moan from his own throat, but Sirius was by far the more affected, his eager mouth showing it, as if the needy moan hadn't spoken for itself. Which is a win for Regulus, because he's not looking to win. He's looking to get Sirius to take his cool down a bit. A win is a win.
And then Sirius plays a dirty trick, because he knows what blood means to Regulus, and bites his lip until it bleeds. And now the kiss is blood and tongue and teeth and gasps and if Regulus hadn't completely lost his mind, he does now. His legs give out, and now he's putting all his weight between the wall and his brother. If Sirius were to just walk away now, he'd fall completely. He doesn't, and Regulus knows there's no reason to worry now.
The metallic taste plays between their tongues, along with some alcohol, and everything Regulus is, comes down to this. The rocking of Sirius's leg against his hips, which he can't say when it started, their mouths joined together and the taste of blood, his own blood, in a sense so deep that if it weren't so hot, it would make him think. The small noises between them, which he can't even tell whose they are.
Until the oxygen runs out, and when they part to breathe, this time, there are no smirks showing off anything. But there is a line of saliva joining their mouths, and he can see some of his own blood staining the corner of Sirius's mouth. Also the labored breathing of both of them filling the desolate hallway is sinking deep into his mind. And he is not aware of how much his brother broke his lip, but he feels the blood running slowly down his chin, and his brother's mesmerized gaze on his lips.
And now Regulus needs to see Sirius bleed. It is a whim he had been thinking about since he discovered how much blood turned him on. And now he is bleeding, and he needs Sirius to bleed too, because he wants to have the taste of their blood together, on his lips. The same blood that runs through two different bodies, and that Regulus needs to taste together, because they were literally made for that.
Sirius seems to read his mind, Regulus thinks, because he smiles, and presses their foreheads together, breathing still frantic and a euphoric giggle in the background. Reg can't quite make out when he started laughing too.
It doesn't last long, though, because Regulus has a vision, and he goes for it. He goes back to the kiss, but takes a moment before deepening it himself. He runs his tongue along his brother's bottom lip first, drawing a sound out of him that Reg wants to hear until the day he dies. And when Sirius opens his mouth to give him access, Regulus doesn't think twice and catches his lip between his teeth.
Sirius tenses, and Regulus smiles against his lips before adjusting his angle to bite down and draw blood, though it also draws a strangled moan from his brother's lips. His lip is still bleeding, and they bleed together now, and Regulus thinks he could die in peace right now.
He deepens the kiss now, and feels the blood running through their mouths as Sirius's hands stop being innocent, and begin their own journey.
They're a mess of saliva and blood and moans and pitiful sounds in the middle of a darkness that could consume them.
But it doesn't. It's surprisingly warm, because it's his, and it's safe. And besides, the heat of their own bodies seems to have consumed the entire place.
And all Regulus wants to do is finish crossing the last line between them. To take himself into a room with Sirius in tow, and fuck him into madness. Or into sanity, given the circumstances.
He suspects Sirius's line of thought might go something similar, if he were given the chance to let him think.
And when he feels Sirius's hands go lower than they should, Regulus knows he has to stop right now. Before he wraps his legs around Sirius, and they fuck in a place where anyone could get to them. He considers the privacy they've had so far a miracle. Not that he cares.
He pulls away against his own will, in a sharp movement pushing Sirius away, because he knows if he tries this any other way, he's going to give in to his own impulses.
Sirius loses his balance a little, and Regulus suspects it's not entirely the alcohol's fault.
Sirius looks back at him, and all Regulus can do is struggle to breathe.
That boy's glare is going to kill him one of these days.
But Sirius seems to get the message, and simply pulls Regulus to Salazar knows where. Not that Regulus was going to ask. Not that he cares, anyway.
They cross what seems like half the castle with Sirius pulling on his hand, chuckling quietly, and running away from Filch and his cat. Which leads Regulus to notice a strange map in his brother's hands, but he decides not to ask.
It's not until they start up the stairs that Regulus realizes where they're going. Gryffindor Tower.
He looks at Sirius in alarm in the darkness, stopping dead in his tracks.
Sirius looks at him, and understands.
Regulus can see the neurons clicking in his head.
"They're at the party, relax."
He can't do it, he can't just relax, even if there's no one there.
But Sirius takes his hand again, and Regulus just doesn't fight it anymore. Not anymore, he trusts his brother for this.
By the time they cross the portrait, the common room is completely empty. Regulus doesn't know if it's because of the time, or the party, but he couldn't care less. They cross to the room Sirius is leading him into, and Regulus doesn't have a second to react before his brother is already on him again. He corners him as soon as he closes the door, and attacks his mouth before he can even get a word in.
Regulus wants to have the decency to put up a soundproofing charm, but Sirius couldn't seem to care less, and Regulus isn't going to fight him because, honestly, they're not his housemates.
So they just dance around in a fight for dominance, because Regulus got a break along the way, and he's not so affected that he stops fighting. They kiss, with blood trails between them, and their breathing ragged, and pushing each other for control. Until Reg pushes Sirius onto the first bed they come across, and climbs on top of him with a smug smile of triumph.
And before Sirius can reply anything again, Regulus attacks his mouth again, and he loses the battle before it even starts.
Until Regulus feels a push, and now they're flipped over in bed, and Sirius is on top of him, and because of the previous position, he's now between his legs.
Reg loses all sense of continuing to fight, he came too far, he tried, but now Sirius was there, and instead of fighting he has to concentrate on breathing properly without making any weird sounds, because his brother is a mess of breathing, and both of their blood staining his mouth.
Sirius takes his hands and brings them together over his head with one hand, immobilizing him. And with the other he pushes Regulus' shirt up, leaving his abdomen exposed. Reg looks at the mess that is his brother, while he looks at him, who is probably much worse off.
He couldn't care less.
Sirius seems to compose himself from the sight, and brings his mouth to his abdomen, and the contact drives Regulus crazy. Sirius stays there, not going down too far, not past his lower belly, and Regulus wants to dig his nails into his hair and guide him, but Sirius hasn't let go for a second, and he's too busy panting to complain.
Until Sirius starts to go up again, and attacks one nipple with his hand and the other with his mouth, and Regulus loses even the ability to think. He's just a mass of low gasps and moans, and he wants to bury his head in the sand the moment he returns to his lips, because Sirius taking his mouth away from his body elicited an absolutely embarrassing whimper from him.
Sirius attacks his mouth, and with the hand that's not holding him he frantically fights against Reg's pants. Which makes it take forever, and makes Reg want to cry, but it's okay.
Because when he does, he lets go of Regulus' hands, and kneels between his legs, putting all his attention into removing his pants, and Regulus props himself up on his elbows to watch the wonder that is Sirius, so desperate and a mess. With his lip busted and his eyes darkened with pleasure.
Sirius brushes his knuckles against his erection through his boxers. And Reg throws his head back in anticipation.
By the time Reg realizes it, he's already moaning into his brother's hands, and Sirius's breathing so close to his own drives him crazy.
Sirius plays with him a little, taking him into his mouth, and pulling out just in time to stop him from coming. Playing with his orgasm and bringing him to the edge, but always coming back. Sirius's fingers preparing him are taking him too far, and he thinks this is a point of no return he definitely wants to take.
"S-sirius, plea-se" he whimpers for the third time.
Sirius's mouth pulls out of him with a sound so sinful it draws another moan from Regulus. But his fingers are still there, still making a mess of him.
His voice sounds so affected when he speaks that Regulus thinks he's being fucked and not himself. It's fucking hot. "Say it. Say you want it, say you want me to fuck you silly, frère."
The nickname comes so naturally from Sirius that it makes him feel sick, and at the same time in heaven. Sirius speaking French while fucking should be illegal. But calling him _brother_ deserves the death penalty. Regulus has always been a little suicidal.
Reg is too upset to notice, but when he speaks again, when he begs Sirius, he does so in French. Maybe that's why Sirius heard him this time.
"fais-le, s'il te plaît, frère, je t'en prie" although his voice is so affected, and close to being a continuous moan, that he is not even sure he said anything coherent.
When Sirius finally pulls his fingers out of him, Reg feels so fucking empty.
Sirius struggles against his own clothes, and when he's finally free, Reg thinks he could roll his eyes just from the sight. He's fully erect, and Sirius crawls over him to kiss him again. One of his hands has taken one of Regulus's legs with it, though, and now they're kissing, and they're rubbing each other with no clothes in between. Sirius is a mess of gasping saliva and trails of blood, and Reg knows he's not much better.
And then Sirius guides himself to his entrance, and begins the slow stroke. Regulus' eyes glaze over, it's more than he could take, and it hurts. Sirius seems to be fighting with himself not to fuck him fast, and Regulus wants this pain to end soon, so he does. He thrusts his hips up, making Sirius moan so sinfully that Regulus forgets his own pain.
They take a few seconds to steady their breathing, and then his brother starts a slow, deep rhythm, and Regulus leaves the pain behind completely to moan into the lips of his own flesh, and blood. Sirius isn't much better than that
It escalates soon, and in the blink of an eye, Regulus is struggling to breathe between gasps and moans, because his brother is fucking him like there's no tomorrow. The noise in the room is obscene, and hot, and he doesn't know where his moans begin and his brother's end
Until he touches something inside him, which makes him let out a gasp, and Sirius seems to get the message, because he doesn't stop hitting him, _there_
Reg comes completely undone, and his vision goes black. His nails dig into Sirius's back, and he just knows he's close.
And then Sirius puts a hand on him again.
Sirius is touching him again, and his hips shake slightly against Reg, erratically. And he fucks him so deep that Regulus just reaches his own limit, and comes. In the midst of the cloud of pleasure, he is aware of two things. The first is that Sirius doesn't stop, he seems intent on reaching his own pleasure, and that is overstimulating Regulus.
The second is that he doesn't take too long. His thrusts become erratic, and messy, and he drives so deep into Regulus that his orgasm seems to rise from the ashes. And then Sirius comes inside him.
He pulls out of him after catching his breath slightly, and simply lies on his chest. Regulus' hand makes a superhuman effort, against all his exhaustion, and strokes Sirius' hair in silence. And this is even more intimate between them, and it is perfect.
And at some point between sleep and wakefulness, Sirius gets up, and cleans them both with a quick spell. Regulus gets up, and Sirius points to a bed next to this one. Regulus' eyes widen in surprise. "So... Who?" Sirius laughs in amusement. “Pete. But it’s okay, he won’t find out.” Reg can’t help the laugh that escapes him, and he doesn’t miss the look of complete adoration that Sirius gives him either.
Then he leaves the bed as if nothing had happened, and takes Regulus’ hand, dragging him towards, now, his own bed.
They fall there, and Sirius simply lets Reg rest on his chest, and they both fall asleep.
Regulus has a suspicion that Sirius is going to regret this tomorrow morning, but honestly? That’s going to be his problem. For now he’s going to enjoy his brother’s caresses on his hair.