Sherlock had very nearly got Mycroft out the door in a towering snit and was feeling positively triumphant until the arrogant prat paused on the threshold.

"Incidentally," Mycroft tapped his umbrella's spike oh-so-casually on the runner, "you really should see what John is up to presently."

"What John does is no conc-"

Mycroft wordlessly held up the surveillance photo.

"It is no concern of mine," Sherlock repeated, but he'd paused just a fraction, was just a bit stiff, and Mycroft smirked.

"It will take him a little while longer to understand he's being-" Mycroft's lips twisted. "-hit upon. He is rather inebriated. Is that wise, given his family history? Well, no concern of mine." He slid the photo into the pocket of the coat hanging at the door. "I shouldn't wait too long, Sherlock, if I were you. Good evening, brother," he said, and tapped down the stair with the insufferable gait of a man who has just landed a particularly well aimed blow.

Only once he heard the black car idling beneath his window pull away did Sherlock snarl.

The photo.

John, at the Swan and Badger. A young man at his shoulder, late twenties, feature writer for a travel magazine, doing well for himself. They'd met at the pub a few times before, chatted, shared rounds, played darts. Darts! John, who could kill a man two buildings away with a handgun, reduced to darts. And not even aimed at living targets. Deplorable waste.

The boy's body swayed toward John. His eyes followed John instead of the projectile. His posture mimicked John's so closely they all but breathed in tandem. In about twenty minutes, he was going to ask John home. And because John really could be spectacularly idiotic sometimes, he would say yes, and not realize the planned post-pub activity was sex instead of football on telly until the child had his tongue in John's mouth. Drunk, lonely, sexually frustrated John Watson, who continually insisted he was not gay but who was addicted to the rush of adrenaline, of surprise, of uncontrolled impulse.

Sherlock briefly contemplated John's state of mind upon waking with a hangover in the bed of an infatuated young man who had offered his body on the assumption John shared his sentiment. It would be Spectacularly Not Good.

There was also the added complication that some unobservant idiots—and it has been established that John is often an idiot—might think the young man bears some slight resemblance to John's flatmate. It really would not do for John to come to this erroneous conclusion. It might make things...awkward. Sherlock had grown accustomed to a high degree of ease between John and himself, and refused to allow anyon—anything to disrupt that.

The best course of action was obvious. For John's own good.

# # #

Draped bonelessly over the sofa, Sherlock heard footsteps on the stair, heard concern and resignation and irritation, and heard too that yes, John was more than a little drunk.

"Sherlock? Got your text."

"Hmm? Oh, right." Eyes closed, he held out an expectant palm. "Your laptop."

There was a long silence. Sherlock kept his eyes closed even as John fought an internal battle between handing Sherlock his own laptop and punching him in the testicles.

A sigh. A rummaging through the detritus on Sherlock's chair. A solid thunk of cold laptop dropped on Sherlock's abdomen, followed by John's footsteps again, this time on the stair to his bedroom.

Some time later, the all-but-inaudible sounds of surreptitious and rather bitter masturbation.

# # #

John woke with a horribly familiar hangover headache and the impression something furry had died in his mouth. Since that was not actually an impossibility in 221B, he was relieved when a tentative scrape of tongue between teeth dislodged no rodent bits. Right. Good. He needed to piss, his right arm was asleep, and there was a spider crawling in his hair.

Oh. Not a spider. Sherlock's nose.

John's entire limbic system stuttered to a halt.

The problem with living with Sherlock, John thought eventually, attempting to ignore the increasingly urgent pressure in his bladder as he lay very still, was that you never, never, ever knew the significance of anything. With some other person—some average, ordinary, normal person—a bloke might make a fairly accurate stab at why his flatmate was in bed with him, sound asleep, one hand on the back of John's neck, face buried in his hair, inhaling short, deep whuffs.

Or, well, no, because that would be hard to explain no matter what. But the point was that with Sherlock, the explanation could be literally anything, and you just absolutely never knew when it was the obvious thing and when it was something...else.

The thing was, if a bloke knew his flatmate was coming on to him, was interested in That Way—if a bloke knew, even a totally not-gay (not that there's anything wrong with that) bloke—then a totally not-gay bloke could come to terms with it. And he could also come to terms with those disturbing not-exactly-totally-not-gay things his body did in response. But no way in hell was a bloke going to put himself through the therapy needed to admit he wished his flatmate's knee were wedged just a few centimetres higher when this whole scenario might be about measuring radon levels in tropical fish.

He lay still, wondering why every bloody morning in London was overcast except the one when he had a hangover. The early morning Saturday traffic noise drifted in from the streets below, and from next door came the unmistakable sounds of Mrs Turner's married ones engaging in enthusiastic marital relations. John was on friendly terms with the couple, had eaten lunch a time or two with them at Speedy's, and found them to be generally good blokes, if a bit dull, but at that particular moment he hated them with spectacular intensity.

John rolled a little to the right to take the pressure off his arm and restore circulation. It was coincidence that rolling pressed his...thigh against Sherlock's thigh. He'd only shifted a few centimetres when the hand on his neck tightened and the whuffing deepened.

"Cigarette smoke," moaned Sherlock rapturously.

John hastily scooted backwards off the bed, nearly getting whiplash as his head was yanked forward in protest. "Sherlock," he said desperately, "let go. I've got to piss."