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Mark was... surprised by Jim’s reaction to Sherlock. He thought that, if he had to worry about Jim’s attention straying, it would be in another direction—a much taller, blonder one; Jim’s flatmate is appallingly handsome, really (though not quite as handsome as Sherlock). But perhaps luckily, Mark and Sebastian hadn’t hit it off—upon meeting Mark, Sebastian had taken one look at him and doubtfully pronounced “B—Jim, that’s a girl.” Jim dragged him out of the room and the next time Mark came by, Sebastian had a partially-healed broken nose and called Mark “Mr. Hooper” slightly desperately.
Except then Jim had come round the lab this morning, and things had gotten a bit... well, the way they always did with Sherlock, awkward and intense at once, and Mark hadn’t actually been that surprised when Jim started tripping over his own words and dropping bowls. Mark occasionally feels like doing the same thing when Sherlock’s watching. He doesn’t think of himself as jealous, and he’s perfectly all right with the idea of Jim being attracted to Sherlock. But.
Mark is most certainly not alright with Jim giving Sherlock his number. Secretly. Especially after the self-satisfied look on Sherlock’s face when he said, very quietly, “Gay.” Even John had rolled his eyes, and Mark hadn’t been able to stop himself snapping back, “Yes, I’ve noticed, because he’s dating a man.”
Right now Mark is standing outside of Jim’s (and Sebastian’s) flat, and he’s going to ring the bell any minute, but first he needs to decide how, exactly, he’s going to handle this. He knows that Sherlock is hard to resist, can hardly fault Jim for less-than-perfect behavior around the man, but—Jim didn’t write his number in the room. He came into the lab with the piece of paper already prepared, with a plan. Which is... weird. Did he know about Sherlock already? Was he using Mark to get close to him? Should Mark be prepared to meet an evil twin next, or for Jim to get pregnant? (Sometimes Mark regrets giving in to Jim’s constant desire to watch Eastenders.)
But standing outside the door isn’t going to fix anything, and may eventually lead to some awkward questions. Mark shoves his hands through his hair, ruffling it further, and lets out a breath, exasperated. Enough, already. There has to be a simple explanation, and he isn’t going to find it out here, is he, so Mark leans on the doorbell and waits.
Jim looks, as always, slightly too pleased to see Mark, and tugs him into the living room by the collar. “Sebastian is out on a job, sweetheart,” he murmurs into his ear, fingers sliding down Mark’s ribs to trace his hipbones, tug at his his belt loops. “And he’s not going to be back for hours.”
“Jim.” Mark does what he never quite wants to, and catches Jim’s wrist. “Stop. We need to talk.”
Jim, predictably, pouts at him, wiggles the fingers on his caught hand. “But we can do that when Sebastian’s here, baby. It’s a waste of an empty flat.”
And oh, but it’s tempting, and Mark has to remind himself that Jim’s behaved really pretty terribly in order to get back on track. “Um. I’d really rather it be now.”
Jim concedes with ill grace, flopping back onto the couch and settling his shoulders further into the cushions. “What, then?”
“Did you—do you know Sherlock?”
Jim’s mouth begins to curl up at the corner, and he reaches for Mark’s hips again. “Is that what this is all about?”
Mark takes a half step back, just out of Jim’s reach, and crosses his arms. He is not going to engage with Jim on this. He’s just going to wait for Jim to explain himself. They match each other, look for look, and then Jim blinks long lashes, slow, and settles back down. Something about the way he’s holding himself has changed, gone dark and focused.
“No. But I plan to.”
That is—that’s just unhelpful, Mark thinks. It’s unsettling, it’s alarming, it’s—well, it’s a little bit sexy, if Mark is being honest, but it doesn’t actually clear anything up. Except that, yes, Mark is pretty sure that anger is the correct thing to be feeling. “How, exactly?”
Jim laughs, crosses his legs at the ankle. “It’s just business, baby. Don’t worry about it.”
“Business? What on earth could possibly be your business with Sherlock Holmes?”
Another laugh, almost a giggle. “He has a very poor grasp on certain operating systems.”
“And you’re—what, you’re tutoring him? He’d clearly never met you, Jim. He had no idea who you were.” Though Mark supposes that doesn’t really indicate anything; not with Sherlock.
“Oh, not teaching him, sweetheart.” Jim shifts, too fluid or too tense. “Playing with him.”
This is unbearable. Jim is stalling, clearly, dodging the question, and Mark just wants a straight answer. “Are you planning to... to sleep with him?”
Jim’s smile turns Mark’s stomach. Well. Close enough to his stomach. “Not planning, no.”
“You—I know you’re not in IT,” Mark hisses, because it’s the worst thing he can think of to say, to show Jim that Mark knows more than Jim wants him to know. He expects an explosion, a fight, is in fact ready for a surge of anger even as he dreads it.
But instead Jim laughs, full-throated, a way that Mark has never heard before. He laughs long enough that Mark moves from confused to angry again, and finally settles, wiping his eyes, though Mark can see that they are dry. “Oh, well done, mouse. Well done indeed.”
“...what?”
“I wondered how long it would take you. Sebastian owes me ten pounds, he thought it would be at least six months.”
“How long what would take me?” Mark’s not angry, not quite, not anymore, but he can’t bring himself to sit down yet, to relax that much.
“Don’t be slow, Mark. How long it would take you to work out that I wasn’t actually involved in IT.” Jim looks pleased, almost smug, which he really shouldn’t. Mark has caught him out in a lie, he has been Found Out, delight is not the proper response, but that grin is doing entirely unacceptable things to his organs.
“Fine. What do you do, then? Why are you even at the hospital?”
Jim taps the arm of the sofa, twice, then he—flickers, almost, and Jim’s sitting upright, elbows on knees. “I’m a consultant, sweetheart. And I’m there for Sherlock. Why else?”
“So, what, you’re... stalking him? What does that have to do with being a consultant?” The tension is draining out of him; he’s abruptly exhausted, unable to maintain this kind of emotion. He drops onto the couch next to Jim—not too close, though. Not yet.
“Come here.” Jim’s voice edges near to command but doesn’t actually touch it; instead he almost purrs the second word, lashes low. “Stalking is such an ugly word. I’m gathering information, that’s all.” His fingers brush Mark’s thigh, light and clever, and Mark softens towards him a little more. Which is stupid, of course, because all Jim is really doing is repeating himself. But.
“Fine, gathering information. That still doesn’t tell me what it has to do with being a consultant, Jim.”
“Can’t give a good consult without it, can I?” Jim is leaning in closer, hand more firmly settled on Mark’s leg.
“I... what?” Mark’s a little too distracted to be entirely sure, but that really didn’t sound like anything that made sense. Is consult a euphemism now? Jim’s mouth is on the skin of his neck, terribly soft, and this really isn’t the time, there’s something off—Mark’s breath hitches a little and Sebastian says, amused, “You have a bed, Jim.”
Oh dear. Suddenly the urgency of the Sherlock situation has receded and been replaced by the much more immediate problem of am I wearing my trousers or did Jim get them off while I wasn’t looking, as well as the back-up chorus problems of how can he be that large and move that quietly and the bass line of hasn’t he ever heard of knocking.
“Oh—” Mark is blushing and Seb is not exactly laughing, one hand half-covering his full mouth and oh dear, this evening is not really getting any easier, is it. Jim giggles, which makes Mark’s fingers go to his belt buckle, just in case. “Sebastian, um, hi. I’m just going, it’s good to see you again, I’m just—sorry, can I get by—”
“Course.” He stands back, barely enough to let Mark squeeze by and, if he’s very careful with his elbows, only just brush the other man. Mark is not careful with his elbows.
He mumbles his goodbyes, half-hears Jim promise to call him. As he’s closing the apartment door behind him, he sees Jim moving in a path that—if he reads it right, which (after two years working with Sherlock) Mark swears he does—is going to end with Jim’s hand directly on Seb’s arse.
Well. Damn.