Sebastian wouldn't deny he was a selfish man. He didn't share, and he definitely did /not/ play well with others. It was a bad enough trait for a normal person, but, when combined with a personality that could only be described as "psychopathic," it could get . . . violent. And the sniper was murderous on his /good days/; this meant that, if Jim played his metaphorical cards right (and he always did, because it was /Jim/), he could push Moran to do truly awful things for entertainment's sake. Oh, and how he /loved/ when Seb got possessive.
Moriarty had been bored for the past week and a half - the only times he wasn't half-tempted to shoot himself in order to find out if the afterlife was half as mundane as reality were when Sebby agreed to play with him, but even that was beginning to lose its charm. Not that he didn't enjoy the sex. He enjoyed it /thoroughly/, but there was only so much he could take before he couldn't walk properly, and, as much as he enjoyed seeing his grunts' reactions, it didn't seem like a very good way to intimidate Sherlock. So, instead, he devised a plan, one that was overly complicated enough to entertain Moriarty for a while.
The second best thing about Sebastian (the first being something that the sandy-blond could do with his mouth), in Moriarty's eyes, was that, even though Moran wasn't anywhere near as intelligent as the consulting criminal himself, he was much smarter than ordinary people. This left Seb in the awkward situation of being keen enough to know Jim was up to something but being too simple-minded to figure out what exactly it was. It pissed Sebastian off - and the angrier he got, the more amusing Moriarty found the whole scenario.
It could have been /so simple/, but Moriarty had never been one to settle for anything less than the most ridiculous plan of action he could devise. That was why he'd reviewed his list of clients (unnecessarily, seeing as he had them memorized, including all of the meaningless little pawns he kept around for days he was starved for amusement), picked out the name of a man who'd been causing more trouble than he was worth in the past month, and told Sebastian to shadow him. He was not to engage, merely observe and report back to Jim with a list of the tall man's preferences. He'd agreed, albeit a bit reluctantly, and returned with an even deeper scowl etched into his features than the one he'd worn when he'd left.
"He's a bloody idiot, that's what he is," Sebastian informed his boss matter-of-factually. He pulled out a cigarette, lighting it and taking a hungry puff before placing it between his lips so he could seat himself on the sofa next to Jim, who was currently stretching his back in a manner that caused his shirt to rise up. Seb knew it was an attempt to make him a little less irritable, and it wasn't going to work, but it didn't stop him from admiring the glimpse of pale stomach he caught before Jim moved, twisting his hips and adjusting the way he sat on the couch so he was leaning against Sebastian's side.
Moriarty wrapped the slim digits of one hand around Sebastian's forearm. It was just muscular enough to ensure there was no chance of his fingertips touching, but he could grasp it enough to squeeze and focus Sebastian's gaze on him. He flashed a playful grin that clashed with the hard gleam in his eyes, and the snap of his teeth meeting at the end of his reply was audible. "I didn't ask for an opinion, Tiger; I need to know what he /likes/~"
Spoken lightheartedly but with a real enough threat underneath: it was one of the things that reminded Sebastian just how mentally unstable his boss was. He liked that about Jim, though. It was sexy as hell when Jim would snap - but it wouldn't be fun today, if the slight curl of the black-haired man's lip was anything to go by. Seb may have been sadistic - and, alright, a bit masochistic - but he wasn't stupid. "He seems t' have a thing for suits," he informed Moriarty, voice only faintly gruff rather than outrightly seething like before. "He drinks coffee. Very American." He shrugged, the unaffected gesture at odds with the way his lip twitched.
"Wonderful!" Moriarty crowed, audibly and visibly pleased. A hand (the one not keeping a firm grasp on Seb's forearm) went to rub Sebastian's chest, the action starting out as approval but turning into one of enjoyment rather abruptly, hand trailing lower, relishing the feeling of thinly clothed muscle. He could feel the encouraging rumble in Sebastian's gut, and it coaxed an even broader smirk onto his lips. He pressed his torso closer to Seb, his voice all but a purr as he leaned forward, nipped at Sebastian's earlobe and whispered how he was going to reward him for his good behavior.