When Sebastian stumbles back into the flat, his first instinct is to automatically head for the bathroom. Find anti-septic, a needle and thread, and a bandage. The wound isn't terrible, he's both given and received non-fatal wounds that are more severe than this one. It's a knife would, low and to one side of his abdomen, deep but no vital organs punctures, simple enough for him, with years of experience in patching himself up, to take care of it.
His fingers are pressed over the wound, blood oozing in between them as he fumbles about in the cabinet for the supplies. He should really be better about carrying them with him when he goes out on a job, but this one should have been a clean in and out. Hiccups happen in plans, however, and this hiccup knifed him. Sebastian isn't one to let things go and that little hiccup is now resting peacefully at the bottom of the Thames with his throat slit and a small 'S' carved over his sternum like a signature.
He glances at the clock on the counter top as he draws the surgical thread through his skin, effectively closing the gash. Jim will be back soon and he needs to have this cleaned up before that happens. Jim doesn't like it when he comes home injured. He says it's because he doesn't like it when Sebastian gets hurt, but the assassin suspects it's really the idea of a plan not going perfectly that bothers him.
He ties off the last stitch and cuts the thread before slapping a piece of gauze over it and securing it down with surgical tape. It will take a few days to heal which means that, unless he wants Jim to find out about it, he'll have to stay out of his boss's bed for a few days.
That's a downside for a number of reasons. First of all, he'll have to come up with a reason for turning down the other man because he just doesn't do that on a regular basis. Second of all, despite what his better judgment suggests, he's rather attached to the strange little man that he works for and he rather likes sleeping next to him. Probably stupid given what they both do for a living but at least he's not attached to someone who opposes his rather morally ambiguous habits.
Sebastian tidies up the first aid kit and places it neatly back into the cabinet. He wipes down the counter to clear off any visible traces of blood and packs his damaged shirt away with the rest of the clothes he needs to have burned, the ones also stained with blood, though not his own. He pulls on a clean shirt and heads back to the bathroom for a final sweep to make sure he removed all the evidence of his impromptu self-surgery.
Some half an hour later, Jim bounces into the flat, filled with an indecent amount of energy for a man his age. Sebastian is seated on the couch, reading the newspaper when Jim throws himself into the man's lap and kisses him hard, fast and dirty before he's up again and bouncing out of the living room, stripping off his suit as he goes.
He audibly rummages around in his room, likely changing into more comfortable clothing for when he inevitably drapes himself across the couch to watch trashy television. Sebastian can hear him move into the bathroom and mentally steels himself, hoping that Jim won't notice anything amiss.
"Seb, what's this?" Jim calls from the bathroom.
He doesn't look up from his paper. "What's what?"
Jim emerges from the hall, bare chested, wearing only a pair of dark pajama pants and holding something between his forefinger and thumb. "This."
Sebastian glances up from his paper. "No idea."
"Looks like thread to me."
"One of your shirts fraying, then? All this talk of your fancy suits and even they can't escape the inevitable." Sebastian smirks.
"It's surgical thread."
Sebastian watches the other man for a moment before shrugging and going back to his paper. "Where'd it come from?"
"The bathroom. You wouldn't happen to know why it was in there, would you now?"
"Wouldn't have asked if I did."
"I know when you're lying to me, Sebastian."
Full name. He's not happy He folds up his paper and sets it on the arm of the sofa. "I'm not lying. I don't know why it's there." Because I'm generally much better at cleaning up, how the fuck did I miss that?
Jim stares at him for what feels like an impossibly long moment. "Strip."
"What's the phrase…ah, I don't believe I stuttered. Stand up. And strip."
"You are not serious." Fuck, he's serious.
He moves to stand directly in front of Sebastian. "Deathly."
Sebastian tries to hold his ground for as long as possible, but Jim's glare is hard and cold and he eventually gives in, pulling himself to his feet, completely in Jim's personal space, barely a hair's breadth between them. He glares down his nose at Jim and unfastens his belt with rough, jerky movements, silently conveying his displeasure to his boss. He tosses the belt onto the couch behind him and shoves his trousers and pants down, kicking them away.
Jim glances down and can't stop the appreciative smirk from sliding over his face, even knowing that it's just going to make Seb even more displeased. He lifts his face to meet the man's eyes again. "And your shirt."
Sebastian bites down hard on the tip of his tongue before reaching for the hem of his shirt and pulling it up and over his head, tossing it to join the rest of his clothes.
Jim's fingers brush over the now exposed bandage. "And what's this, then?"
He deliberately avoids Jim's eyes. "Just a scratch." He jerks hard and bites back a groan as Jim's quick fingers grab the edge of the surgical tape and rip the entire covering off. Jim drops the bandage to the ground and traces along the edges of the stitches with his fingers.
"Looks a bit more serious than a scratch to me." His gaze flicks up briefly to Sebastian's faze again before he presses down hard on the gash with his thumb, digging in hard enough for bursts of red to leak around the edges of the threads.
The taller man can't stop the groan from escaping his mouth this time. He knows Jim is angry with him and that this is supposed to be punishment but fuck he loves the way that Jim hurts him.