By the end of the first week they already have a routine; Dave will be sitting on the couch, or in bed, and Karkat will come up behind him and lean against his back, chin heavy on his shoulder, and Dave's heartbeat will speed up.
Karkat doesn't like to ask out loud. Sometimes he grumps that he's hungry, like an accusation; sometimes he doesn't speak at all, just watches Dave with speculative wild beast eyes, how best shall I devour the flesh off your bones, O talking meat.
Dave is an obliging guy, so he's not very hard to convince to put a hand down the front of his pants and grab a handful of his stirring dick.
Often Bowie caws out a mocking laugh, or starts grooming to pretend boredom. (Karkat has no daemon to groom while Dave caresses his armored arm and tightens the hold of his gauntleted hands around his ribs.) Tonight she just stares back at Karkat, perched on the back of the couch. Karkat's teeth are nibbling thoughtfully at his neck and despite how that makes him breathe faster, the wet-warmth and the idle threat, Dave knows his demon isn't paying attention to him, is staring up through his wild mess of bangs at the bird that is the other half of Dave's soul.
Karkat's teeth barely dent his skin, he doesn't even want to play with the risk of drawing blood without orders and besides Dave's been losing too much of it recently. He licks a tentative stripe up Dave's neck, and Dave groans, not all from sexy. "Gross, too much saliva."
Karkat teaching himself how to play him like a violin, though, that's sexy.
Karkat bumps his cheekbone into Dave's jaw, a pointed reminder, and Dave obligingly goes back to pumping himself hard. It's a bit weird that Bowie is sitting here staring -- it's not like she's never seen him jerk it but usually she doesn't watch.
He thinks maybe she guessed what would be coming next before he figures it out.
Karkat's hold tightens on his waist and he grunts; his wings come up to curl around Dave's shoulders (can't curl farther to surround him, too short, wrong angle, but something corvid inside him can't help but hunker down, push back into it.)
And then he reaches past Dave and he touches Bowie.
No one's ever, not since, was it Rose, eleven and gangly, was it Bro, Dave's leg broken and Osprey-Bro unable to pick up Bowie without hurting her worse? He can't remember but it was so long ago, it was before, she wasn't even a bird yet. (Snow-white already though.)
Armored knuckles light on chest feathers, running down her throat -- his throat, Dave can feel it on his skin, through his skin -- down under her, nudging her legs like, like --
She hops up on his fingers and he lifts her, pulls Dave backward until they sprawl in the corner of the couch, Dave stretched out with one leg on the cushions and one underneath the coffee table, stuck in the hollow between Karkat's body and the back of the couch, and Bowie -- Bowie, oh shit, oh fuck, Karkat bringing her to his chest, letting her hop down on his bright hard plastron, resting his heavy demon claws on her back.
She doesn't even flap her wings; she goes, hunkers down in the crook of his neck, and they croon at each other like a crow and a rusted metal cricket-crow a little bit in love.
Dave can't feel him like he would a human touching his daemon, soul to soul, and it's a bright sparkle of unexpected pain. He wants, he wishes Karkat had an animal soul to cradle, he wishes he would ever be allowed to touch it -- hah, that would never happen. At the same time -- at the same time his head is craned and he stares, so close his breath washes back to him as he pants, someone else's hand on Bowie's back.
Ivory feathers and hard flat shell, white and gray and artery red, her eye and his flesh underneath.
Karkat's hand is so cautious on her back, claw tips held raised so he won't even brush her, and when she preens one of his bangs he closes both his eyes on that side and makes a little startled pout.
Dave's hand on his own dick is nothing like cautious, it's tight and hard and fast, and when he comes he arches so hard he shoves Karkat into the cushions and makes him grumble against his skin.
Soon it becomes purring, as Dave goes loose all over his demon, as his daemon's wings spread boneless on hard-shelled clavicles, the chiseled curve of a blade-tipped shoulder. Karkat feeds, mouth open wet against his skin, suckling lightly even though there's no blood to be had. His arm is still wrapped tight around Dave's ribs, his other hand still on Bowie's back, like he wants to make sure they don't wander off.
They like that, there's no need to tell each other so, to even look at each other, they both know it.
Soon he's going to shove them both off. For now, he feeds and they bask.
The next day on patrol she perches on Karkat's shoulder instead of Dave's, and when Jade's Sievert tilts his weird pointed thylacine nose at her she fluffs her wings and says she gets a better look at the clues from this level. Dave sticks his hands in his pockets and ambles lazily away from Jade's not-fooled eyes.