This is an extremely late birthday fic for Tara (Caederam) because she loves slash, and I've never written it before. Here you go. It's confusing and a bit odd/off and I'm not really sure I understand it, so good luck and happy birthday :)
You go out like a rip-tide
Travelling swallowing Dramamine,
feeling spaced breathing out Listerine
~Modest Mouse~
Your relationship with him has always been different to yours with James, but then, you suppose, he and James, for all their similarities, are two very different people. His relationship with James is different again from yours and his. Their love, it's the forever kind, the you're more me than I am kind, the we could be brothers but we're so much closer than that kind, the totally platonic kind. But you and him, you're different. It's the kind of love that burns and consumes and destroys, it's dangerous, it's the love that you hate as much as you crave it. It's when you can't get close enough to the other person, the kind where you want to live them, breathe them. Where you want to tear them open and curl up next to their warm-and-beating heart and then sew them up again with a needle bigger than your arm, long, sloppy, jagged stitches, messily tied off at the ends and tugged tight-tight-tight so that none of their precious blood would escape, and then you'd wrap yourself up in his bones, and blend into his blood, and press your beating heart tightly against his and then maybe you'd be close enough, maybe it would stop this burning aching pain that consumes you and burns you and tattoos you with desire.
Your lips trace his collarbone, whispering secrets he'll never hear against his smoky skin, and as your fingers brush over his spine, counting every ridge in his back, you feel him shudder below you, shudder and shiver and maybe those black ragged wings you've seen hovering inside his ribcage are ready to burst free, to burrow their way through his bones and tear their way out through his skin and sweep the sky with inky feathers, shedding his plumage like droplets of treacle obscuring your vision, drowning you-
Your love is smoky cigarettes and barbecues that won't ignite and bonfires that will, and smashed lager bottles that leave invisible shards on the floor only to be trodden on weeks later when you've forgotten to wear shoes, and jutting hipbones and t-shirts thrown off the sofa and cold empty beds and open windows and the stale smoke and old lager and ash smell he leaves tangled in your sheets.
His slim fingers ghost over your sharp hipbones and you moan into his inky hair, stale smoke winding down your throat and coiling in pale wreaths inside your lungs, your lips crashing together, teeth chink and tongues delve and devour and crave, messy breathing hitching in between and your breath tangled together, out of his lungs and into yours, wrapping and squeezing and merging together. Your breath is his breath, your skin is his skin, the goosebumps tracing their way up your arms and curling around your spine are his-
You remember the first time you saw him, that small and skinny boy with too long too black hair that hid his face, his chin high and thin shoulders squared, and you remember the way those same shoulders shook that night as he lay in the wrong bed in the wrong common room in the wrong house. You remember the first time you saw him smile, you remember the light in those eyes that were too big and dark for such a thin, pale face, and you remember the first time you saw that light go out. You remember the first time he didn't sleep in the round room with the five beds, and you remember the anger you felt, and you remember the pain in James' eyes that was mirrored in your own and you remember the apologies, the way those eyes were surrounded by purple bags and you remember the not-so-thin-any-more shoulders slumping, and the still too long too black hair falling forward to hide that thin face with the high cheekbones. You remember the first time you kiss him and you remember the taste of firewhiskey on your tongue and cigarette smoke in your throat and you remember the way he was too close and not close enough in the corner of the dark smoky room and you remember the hangover and you remember not remembering and you remember the second time you kiss him, and you remember the absence of firewhiskey but the cloying sticking consuming presence of the cigarette smoke and the ash that falls like rain from his skin and sinks into yours, the ash that gathers in drifts in your ribcage and settles on your tongue.
He arches up into you, throaty moans escaping from his bleeding lips and curls up against you, lips claiming yours in one of the sloppy kisses you never get quite in rhythm, your teeth clashing in the way that's more familiar to you than breathing, and the never-leaving whisper of ash against your skin-
If someone were to ask you when it was that he started smoking, you wouldn't have been able to tell them. You doubt even he could. It's something that's always been there, as long as you can remember, the smell of smoke and the ash-stained fingertips are as much a part of Sirius as your 'furry little problem' is of you. You can no more imagine Sirius without the fog of smoke than you can James without his obsession for Lily. You think maybe it's something that's grown with him, maybe he was born with a fag in his hand, maybe the ash is secretion from his skin and maybe tar runs in his veins instead of blood, perhaps his bones are built from stubbed out ends of cigarettes and his skin is smoke made tangible, moulded together and stretched thin, wrapped around his bones like bandages round a mummy, and if you were to slit his skin grey vapour would float out and he'd deflate like a balloon and collapse into a pile of ash.
Love you, he mutters in your ear, in that beautiful haze before sleep, and you laugh a little and affectionately run your fingers through his inky hair. This time is the only time he's gentle, the only time he speaks, the time he'll press a kiss against your jaw because he feels like it, the only time there's any affection or emotion or anything other than lust and desire and I need you now, the time he'll tear himself open to let you leap inside and nestle in his ribcage. You hold on tight to these moments when they come your way, grasp them and fling yourself at them and try to wrap them up inside you so they can't escape from you, but you know they'll pass you by so you drop a kiss to his forehead and whisper close into his skin.