The sounds next door were still crescendoing as Sherlock finished his wank, clutching a tissue and balancing a chemical equation in his head. The last coefficient slipped neatly into place just as orgasm gripped him, and the resulting contraction of pleasure was both physical and mental, which had recently become his favorite sort. Sherlock lay still for a few moments after, tingly from hyperventilation (his carefully-timed gasps had been covered by his neighbors' noises), feeling a deep satisfaction with this still relatively-new state of affairs. Previously he had induced sleep via the recitation of well-known information -- the elements by atomic weight, or the times tables through thirty -- but all too often his own brain had betrayed him, catching him in hypotheses and theories which brought him in quite the opposite direction than intended. Instead of being lulled into a stupor by contemplating such basic data, sheer perverse boredom had frequently driven him into the heights of abstract wakefulness, until nothing would quiet the whirling numbers and formulae except attacking the violin downstairs. John had not cared for that method.
This, though, ah. Sherlock had never ventured far into the realm of physical pleasure; messy, predictable, ordinary. An animalistic activity with no reward except a wet spot and lost time. It had never occurred to him, though, that in combination with mental exercise it was the very thing for putting one to sleep. Orgasm, he had been surprised to learn, produced a sort of lassitude that strenuous physical exertion did not. On the nights when he was too keyed-up to even lie still in bed, a wank and a series of balanced equations was generally enough to win him a few hours of sleep. A useful fact.
John certainly preferred this method.
Sherlock didn't know, of course, that John understood about the sleeping. Not like he knew the color of mud in the Brixton Road or the tones of the diatonic scale or the number of phalanx bones in his hand. Not even like he knew that the postman had given up chocolate for Lent or that Mrs. Hudson's niece would call tomorrow at precisely ten a.m. Sherlock's conclusions relied on data, not intuition. Not soft imprecise mutable things like feelings. They never spoke about it, and it didn't happen above once or twice a month. But whenever the ennui of ordinary life had driven Sherlock into a quite unbearable mania, whenever his choices seemed to be between hunching on the bed all night tearing at his fingernails while his brain spun or seeking out his old supplier in Southwark, John would slip out quietly and come home later, rather less quietly, with company. And then Sherlock could, with great relief, stretch out and surrender to the two types of exhaustion. A good night's sleep for everyone followed.
He didn't absolutely know that John did it on purpose. But, reluctantly, he felt that it was so.
Sherlock had not expected to discover that he required external stimulation. His brain was one of the world's great treasures, a storehouse of information and images and ideas, enough to entertain anyone for a lifetime. But he was not just anyone, and perhaps after all the contents of his own brain were too well-known to be of use to him. He had tried, once or twice, to explore the usual options on the internet, and had retreated in horror. Ordinary, quite ordinary. To be aroused by such tripe was to declare oneself a base thing, a troglodytic lump of nerve endings and cliches. But when he attempted to consider what he himself, an extraordinary being, might find arousing, his mind shied away like an uneasy horse. To take a thing like a body, an object, and assign a sexual value to it was vaguely alarming. He was all too aware that the things he found worthy of his interest, corpses and half-smoked cigarettes and bloody left boots, made other people nervous. That was their lookout, and he didn't give a toss whom he made nervous if he solved a case. But what if he should unearth a sexual interest in a thing like that, like rubbish in a muddy river bed? Would Donovan and Anderson and half the people he'd met in his life be proven right? More importantly, would it impact the work?
So Sherlock left the depths of his inner consciousness unplumbed, because once again John had been an unlooked-for source of help, in his mundane way. Sherlock had tried, just once, to wank when John was out of the flat, and it had been a miserable failure. Atomic weights were not arousing. Previous cases were too dangerous to be arousing; what was the difference, really, between a beautiful living woman and a beautiful dead one? He had to admit he was lacking in resources. He had given up, stayed awake for three days until John came back from visiting his old schoolmate, and presumably been so wild-eyed that John had grasped the situation at once and gone back out for a pint. It had been a long hour for Sherlock, pacing his room and tying knots in the belt of his dressing gown, and when John had returned alone the disappointment had nearly made him pop his head out the door and shout in frustration. There had been nothing to say, though, that wouldn't have upset the strange tenuous fragility of their arrangement, and when after a minute he'd heard John lie down on his bed, and the sound of the zip on his jeans (oh, Sherlock's hearing was very good), understanding had dawned. John hadn't made much noise, just a gasp or two and the slick good sounds of him stroking himself, but it had been enough to flip whatever mysterious, maddening switch Sherlock's brain required. That orgasm, wrung out of him like a sneeze, had put him to sleep for sixteen hours, and he'd thanked John by leaving off his kitchen experiments for nearly a week.
Things had started that way, and Sherlock was forced to admit that in this, as in so many things, he and John were irrevocably intertwined. He'd never suspected that masturbation might be a sleep aid until that night five months ago, and he hadn't been moved to masturbate in years until the low, husky sound of John's voice during intercourse had aroused him past resisting. That had been shocking enough, but not as much as the fact that John, upon discovering this, had seemed to like it. Had been aroused by it in turn, judging by the state of his pyjama bottoms after he'd talked Sherlock through a spectacular orgasm. Had kept this whole strange affair going for months now, bringing home girls he didn't introduce to Sherlock in the morning and shagging them loudly and thoroughly while Sherlock listened in the next room, putting himself to sleep with chemistry of the body and the mind. An unconventional arrangement indeed, but Sherlock was hardly one to insist on convention.
The loud and thorough shagging next door seemed to be coming to an end, Sherlock thought, wiping himself with the tissue and tossing it near the wastebasket. John's mattress creaked in a faster rhythm, and the volume of the girl's cries was increasing. John himself was strangely quiet, but as Sherlock no longer had need of that particular stimulus it hardly mattered. One last sound from the girl -- more of a yelp than a cry -- and silence fell. Sherlock closed his eyes, settling down to sleep, and was on the very edge of losing consciousness when the door to John's room banged open, followed by the sound of unsteady heels clomping down the corridor. The door to the stairs was the next victim of heavy-handedness, and Sherlock could just hear the street door receive the same treatment a few seconds later.
Odd. John tended to be more chivalrous than that. Breakfast, at the very least.
Sherlock opened one eye, considering his dim ceiling. There was a certain experiment concealed in the back of John's wardrobe which he had been intending to retrieve for several days. Hopefully without John's knowledge, of course; he had a strange attachment to his cheap, well-worn clothing, and was likely to be rather upset about the fungus. Now might prove an excellent time for a covert retrieval, as Sherlock was fairly certain the alcohol John had undoubtedly consumed (never less than three pints, by this time of night) would have put him into a deep sleep. Too much physical activity at this point might, on the other hand, impede Sherlock's own ability to sleep, but the sacrifice was worth it. He'd definitely slept at least one night this week, as far as he recalled.
Deciding to risk it, Sherlock rose from his bed, leaving his dressing gown behind. He opened his own door soundlessly, and was unsurprised by the dim yellow light spilling into the corridor. John frequently slept with his desk lamp switched on. The girl hadn't fully closed the door behind her, and Sherlock placed a hand on it, pushing it open just a tiny bit further to peer into John's room.
John was lying curled on his side, his back to Sherlock. The blanket had been pulled up just to his waist, and he was still wearing a blue-striped shirt which, judging by its looseness, had been unbuttoned. Sherlock watched him for a few moments, tracing the pattern of his breathing. The rise and fall of his shoulders was inconclusive. Sherlock took one more step forward, pushing the door open wide enough for him to pass through, and John rolled over.
Sherlock ceased all movement, going inert, every muscle in his body completely still.
John was wearing neither pants nor trousers. Not a surprising fact, given that he'd just engaged in intercourse. He tucked one hand behind his head, which pulled his shirt open to reveal the thin white vest beneath. His other hand was wrapped around a completely surprising erection, which he was stroking beneath the blanket at a slow, languorous pace.
"Hello," John said.
Words formed, crowded, multiplied, stuck in Sherlock's throat. His mouth was dry, tongue paralyzed. He'd felt like this once before in John's presence, the night John had caught him wanking and had asked him terrible, unanswerable questions with a smile in his voice. Sherlock hated feeling like this.
"Where's -- your friend?" he managed, after a moment.
"Off to catch the last Tube," John said.
"Ah," Sherlock said. "I thought you..." He didn't finish his thought, because he couldn't think. This was a catastrophe, a disaster of unimaginable proportions. The mere presence of John's half-naked body and act of self-stimulation was breaking down his splendid machine. This, this was why Sherlock didn't involve himself in the physical sphere.
Sherlock shut his eyes. Vision was only one of five senses. Four were more than enough to gather meaningful data. John didn't sound like his usual self; his voice was thickened, slower. There was a scent on the air, sharper than mingled sweat and bodily fluids. He couldn't touch John, couldn't taste John. He didn't need to.
"You're drunk," Sherlock said, eyes still closed.
"Got it in one," John said, with a sigh.
There was a wet, obscene sound, one Sherlock knew very well. He dredged up a fact learned somewhere once, shelved deep due to its irrelevance to his life (alcohol and sex were opiates for an entirely different class), which explained the hasty female departure and John's curious continued tumescence.
"You couldn't achieve orgasm."
"And your friend..."
"Got hers, then buggered off home. Something about work in the morning."
There was a pause, brief but significant.
"You might help out, you know."
Sherlock blinked his eyes open, the room blazing into his vision like an overexposed snapshot. John was gazing at him levelly, still with that maddeningly relaxed pose, still stroking himself, the tip of his erection just protruding above the blankets. The curtains had been pulled partway shut. There was four pounds sixty in coins on the desk. John's mobile was still in the pocket of his trousers, which were halfway under the bed, and tomorrow he wouldn't remember where it was. Books stacked at the bedside indicated John was considering a trip to the west country; a book by the window indicated he was concerned about his financial ability to do so. Sherlock noted all these things, trying to pretend they were equally important, trying to believe that his inebriated flatmate in a state of frustrated arousal was no more relevant than the number of pound coins on a desk or the amount of dust on a bedpost. Trying to see John as a data point.
"Help?" Sherlock asked. He intended to pack the word with disdain, and succeeded only in sounding puzzled.
"Yeah," John said. He indicated the empty space beside him with a jerk of his head. "You could -- sit here, all right?"
It was not all right. Nothing had been all right, as far as Sherlock was concerned, since he'd entered the room. But John sounded so reasonable, and gentle, and a bit pleading, and Sherlock couldn't forget the nights of deep and pleasant sleep he'd been enjoying recently. Obligation was a new feeling since John had come into his life, yet John rarely presumed on it. Sherlock knew he'd ruined dates and shirts and appetites and afternoons and once, very nearly, John's birthday. And John almost never asked for anything in return, even when he was so angry his hair stood on end. In short: Sherlock owed him.
"All right," Sherlock said, and climbed, stiffly, onto the bed.
It took him a moment to settle in, sitting bolt upright against the headboard with his legs stretched out. John left off wanking and just watched him, catching his bottom lip between his teeth. Sherlock looked straight ahead, but John was there in the corner of his vision, daring him to look back.
Once he'd gotten as comfortable as seemed likely, a somewhat awkward silence fell.
"Is this all you wanted?" Sherlock ventured at last.
John shifted on the bed next to him, making the mattress rise and sink. "No."
Sherlock's chest felt tight, an illusion created by a heightened emotional state but distressing nonetheless. "John, I'm afraid I can't -- I don't -- "
"Just talk to me," John said softly.
Sherlock looked down at him, catching in a swift breath. The phantom chest tightness continued, along with the utterly false sensation that his heart had actually leapt up a fraction. Bodies, he thought, were truly useless. Why waste so much blood on an increased pulse rate, making his ears pound so? Why devote energy to the production of the adrenal fluids that sought to make him believe he was in a fatally dangerous situation?
(Except there was danger here, yes, danger in the softness of John's eyes, the way his body craned towards Sherlock's like a flower following the sun, in the sweat breaking out on the backs of Sherlock's hands and the fact that four words from John's mouth were enough to dismantle everything Sherlock had built for himself so effortlessly through the years. So bodies perhaps knew what they were about, once in a while.)
"What should I say?" Sherlock asked, around the tightness in his rebellious throat. Why was his body cutting off his access to oxygen, just when he most needed to be clear-headed? At any ordinary moment he would have had a hundred things to say, a hundred scornful arguments as to why John was asking the impossible. All logical, all reasonable, all damning and perfect and exact and true. None of which would give away the soft secret shameful other truth, that being on this bed with John made him feel like a backward child, shut out of life with no way in.
"Say -- ah -- anything that comes into your head," John said, beginning to stroke himself again, hips straining up.
"Eighteen times twenty-three is four hundred and fourteen," Sherlock answered, to be perverse.
John laughed, low in his throat. "Need a bit more than that."
"Eighteen times twenty-four is four hundred and thirty-two."
This time John's laugh was mixed with a sigh of exasperation. "Have you really never done this before?"
John was looking at him again, Sherlock knew, as he fixed his own gaze on the wall opposite. The room had been re-papered at least twice. The second set of paper-hangers had used an inferior sort of glue. He clenched his jaw slightly. "No."
"Ah," John said. "I had wondered."
There was a lot left unsaid in the pause that followed, and they both went on not saying it. Sherlock wasn't drunk. He wasn't going to lay bare his little encounters, his assignations, which had previously been about as interesting to him as cataloguing every time he'd vomited in his life. Two kisses in his teens, both girls, both at family weddings and induced primarily by champagne. One wank circle in the fifth form, a ghastly experience assiduously avoided in the future. One handjob (receiving) his first year at university, one handjob (giving) his second year, both men, both anonymous, both experiments inconclusive with regards to his sexuality. By his third year he had no longer cared.
"I don't know," Sherlock said, and stopped. "I don't know what to say."
"Well that's a first," John said, and his voice was so delighted Sherlock couldn't help but look at him.
This was John, relaxed, comfortable, not taking up too much space but a solid presence in the space he did take. John with an amused fondness in his eyes, the expression Sherlock liked best, even though he seemed somehow driven to consistently provoke its opposite, the tight exasperated barely-constrained anger that tugged at the small part of Sherlock that experienced something like fear, saying He might leave one day, you know, and it will be your fault. And Sherlock, to spite that part of himself, to poke and prod and crush that weakness, would say the one precise thing guaranteed to push John over the edge, whether into a full-blown row or his bedroom or the street.
But John never left, not really.
"I want to watch you pleasure yourself," Sherlock said, and winced, because that was the wrong word. John laughed a little, at him, with him, and did as Sherlock asked.
"This good?" John asked, his hand gliding up and down his shaft.
"Yes," Sherlock said. "Although, perhaps a bit faster. No. Do it exactly as you like it."
"That's easy enough," John said, closing his eyes. He struck a middling pace, no urgency, just steady and good. Like himself.
John's lower body was still mostly covered by the blankets, and Sherlock liked that. The wet, red tip of his erection appeared and disappeared under John's hand, but Sherlock was more interested in studying the rest of John. The dark hair of his groin turned sandy further up, narrowing into a line that continued under his vest. He had the slightly soft middle of a man who was no longer young, but the muscles of his stomach were tensed. There was more sandy hair above his neckline, somewhat sparse, and the muscles of his shoulders and biceps were still quite visible through his button-down. The lines of his forehead were more prominent than usual, as he frowned in concentration, but his mouth was relaxed, partly open. Sherlock focused his observation there, watching John breathe, watching his tongue briefly swipe his lower lip, watching his lips purse with a slight grunt of pleasure when he found a good rhythm. It was just a mouth, meant for mastication and speech, but as he watched Sherlock began to understand why it might be arousing. If he pressed his own mouth there, he would taste John, his lips and tongue and breath. John might use his mouth, in turn, to produce sensation on some part of Sherlock's body. John might lick, or bite, or kiss. There were a hundred possibilities, all there in his soft, full, tempting mouth.
It was pedestrian. It wasn't much. But it was a start.
"Your mouth," Sherlock said.
"It's..." Sherlock thought. "I think I want to do things to it."
"Things, Sherlock? That's terribly imprecise of you."
Sherlock drew his knees up and laced his fingers about them. "It's only theoretical."
"But I think..."
"I think I'd like to put my fingers in your mouth," Sherlock said, looking at his knees now. "I think I'd like to feel your tongue, have you bite me. I'd like my hand to be slippery with your saliva, and smear it on my own mouth, and taste you."
He felt John stop moving, and he heard John swallow.
"That's... very precise," John said.
Sherlock knew he'd said something wrong, and raged silently. Whatever comes into your head, John had said. It wasn't his fault his head wasn't like other people's.
"Sherlock?" John asked, and Sherlock turned to meet his eyes, with a feeling of resentful pride. John looked somewhat shaken, flushed and breathing fast, but he was also looking at Sherlock with the faint wonder and admiration he'd never lost since the first time they met.
"Keep talking," John said.
John went back to stroking himself, and Sherlock let his gaze roam all over John's body, seeking inspiration. John seemed to have quite a ways to go yet, and he wondered what it had been like earlier, when the girl was here instead of him.
"What was your friend like?" Sherlock asked, following up on this line of inquiry.
"Mm. Blonde hair. Small. Good legs."
"Her breasts?" Sherlock asked, because he knew John cared even if he didn't particularly.
"Really nice. Halter top, no bra. They practically leaped into my hands."
"What did you do first?" Sherlock asked, even though he knew.
"Ah," said John, and smiled. "Got her skirt and knickers off and got her spread out on the bed. I could have eaten her out for hours."
"I doubt she would have withstood that, judging by the noise she made," Sherlock said. He thought of John's mouth again, licking, sucking. He wondered if John knew how to do that to a man as well as a woman. He wondered if it was something he would enjoy.
"It was the best bit, anyhow," John said. "By the time I got the condom on, my head felt like it was wrapped in cotton wool."
"That didn't stop you fucking her," Sherlock said, and it felt like the first time he'd ever said the word. It was thick and heavy in his mouth, the f catching on his bottom lip, the k in the back of his throat.
"No," John sighed, and stroked himself a little faster. Sherlock's restless gaze had settled and their eyes met again, with an intensity that brought back that tightness in Sherlock's chest.
"It sounded -- good," Sherlock said.
"The bed was creaking."
"You were -- breathing hard. Groaning."
"I remember," John said, closing his eyes for just a moment.
"I could hear everything perfectly, through the wall."
"What were you doing?"
It was Sherlock's turn to close his eyes briefly. He was beginning to get a sense of this, how the words meant nothing and everything, how truth and fantasy mingled. He was, after all, the cleverest man in London. Possibly the country. The world was not out of the question.
"I was stroking my cock, listening to you," Sherlock said. He didn't say anything about the chemical equations.
John moaned a little, lifting up his hips. More of his erection showed above the blanket and Sherlock began to be interested, now, in seeing the rest.
"I was thinking about you pumping in and out of her," Sherlock said. It wasn't exactly a lie. "How slick and wet she would be, her vaginal folds stretched out by your cock."
That might have been a bit clinical but John didn't seem to care, his breathing speeding up as he wanked faster. Sherlock saw the flush creeping up his chest, noting the signs of heightened arousal. This was his territory, understanding the whole from the details, particularly anatomy, and he could feel his confidence returning. He stretched his legs out on the bed again, dropping his hands to rest on his thighs.
"I wondered about your cock," Sherlock said, because that word seemed to touch something in John, making him shudder every time Sherlock used it. Interesting. "How big it was. How thick, how long. Whether it looked like mine. What you looked like when you came."
John was positively panting now, and Sherlock felt he had regained himself. Sex was not, after all, a separate thing, merely a new branch of knowledge. Ten times a day he said something to John knowing what its effect would be. Saying things to bring him to orgasm was no different, really, and truthfulness was no more necessary. It was simple cause and effect. John closed his eyes, and Sherlock let himself smile in mild triumph.
"I want to see you now," Sherlock said. "I want to see you wanking, want to see you come."
John reached down to push the blankets away, and this time Sherlock was prepared for his own physical reaction. He firmly quelled the sudden increase of his pulse, breathed through the slight catch in his throat, and studied John's cock. It looked like it belonged to him.
Sherlock was so intent on his detailed observation of John's anatomy that it was a surprise when the body in question began to move. He looked back up again to see John sitting up, propped with his hands behind him and his shoulders rising and falling quickly. His hair stood up in tufts, and there was something hard and fierce in his eyes that Sherlock had only seen a few times before. It usually meant danger.
"You want the show?" John asked.
Sherlock swallowed, hard.
John attacked him, pressing Sherlock flat against the headboard with his hands on his shoulders. Then he straddled Sherlock's legs, his bare thighs tight around Sherlock's clothed ones, and lifted himself onto his knees. He braced one hand on the wall, behind Sherlock's head, and reached down to pump his cock with the other, rough and fast.
All of Sherlock's regained composure melted away, a solid boiling into a gas in a moment of sublimation. His mouth fell open, words blockaded behind each other, higher thought as impossible as drawing a measured breath. John's face was inches from his, breath coming in hard quick puffs, and the scent of whiskey reminded Sherlock that John had been drinking, was possibly not in possession of his full faculties, and was wanking onto Sherlock's lap as if it were the only thing that mattered.
"John," Sherlock managed to choke out.
"You want to see?" John growled. "You want to watch?"
Sherlock looked down at John's hard, swollen cock, dripping at the tip, and groaned. "God."
"I'm going to come all over you," John breathed. "Tell me how much you want that."
Sherlock did want that. He didn't want that. It was the same thing. He watched John stroke himself with half-closed eyes, his head light and spinning, and fisted his hands in the sheets beneath him.
"Tell me," John said.
"I -- " Sherlock panted. It was too much, he'd never felt like this with another person so close to him before and the loss of control was electrifying. Everything was arousing him, the sight of John in front of him, the pain in his head from being knocked against the wall, the fact that he couldn't get a deep breath. He needed his facts, his equations to keep him from flying apart.
"Did you mean what you said?" John said through gritted teeth. "All that before? Or were you just saying what I wanted to hear?"
Sherlock closed his eyes and shook his head, his hair brushing across his forehead. Yes, he thought.
"Sherlock," John said, and there was a pleading edge in his voice. "Say something."
Sherlock opened his eyes, saw John stroking himself desperately fast, his balls swaying and the head of his cock dark and wet. He looked up at John's face, that lush mouth hanging open, John's eyes worried and hopeful and nearly crossed with incipient orgasm.
"John," Sherlock said, the only thing he could say, the only possible thing there was to say, and John groaned and came all over Sherlock's stomach, hot gushes that made Sherlock gasp as they soaked his shirt. Sherlock kept his eyes on John's face, as John closed his eyes and bit his lips and tossed his head to the side in what almost looked like pain. When he'd finished, John leaned his weight on both hands against the wall and dropped his head, his nose just barely touching Sherlock's.
They breathed together. Sherlock closed his eyes against the assault of physical sensation; John's legs were still pressed against his, the come on his wet shirt was rapidly turning cold, and John's breath smelled less like whiskey and more like himself, that mysterious blend of scent that had no physical descriptors and which Sherlock would recognize anywhere by now. John moved his head just slightly and then his mouth was so close to Sherlock's that Sherlock wasn't sure, for a moment, if they'd made physical contact. He could halve the distance, he thought. John could do the same. And they'd go on halving infinity and never reach each other.
John's chest swelled with a sudden catch of breath and it was enough to move their mouths together, his bottom lip just brushing Sherlock's top lip. Sherlock heard the wet sound of John's tongue as he swallowed, and realized, amongst all the tumult of sensation, that he had an erection. His heartrate increased as John turned his head to the side and back, not kissing Sherlock, just sliding their mouths together hesistantly like he was testing something. John shifted his knees on the bed, which made Sherlock's pyjama bottoms pull tighter against his erection, and Sherlock made a small sound under John's mouth, entirely without meaning to.
John froze and Sherlock's eyes fluttered open. Their faces were too close for him to meet John's eyes properly, and Sherlock tipped his head back, breaking contact. They stared at each other for a moment, breath mingling again. John lifted one hand from the wall and slid it down to rest on Sherlock's shoulder, with a questioning look.
Sherlock thought about all the inherent possibilities in that hand, John's hand, and about pleasure and losing control and finding it again, and felt a curl of pure, animal fear low in his belly. He shook his head, a slight movement against the wall.
"Not yet," Sherlock said, very quiet, and John nodded.
Sherlock sighed deeply, and John moved away, falling onto his side with a heavy, boneless bounce. He yawned, half-laughing, and stretched his legs out.
"Well, that's got me knackered," John said, in an ordinary voice. "Er. Sorry about the mess."
John reached over to touch the wet spot on Sherlock's shirt, with a rueful smile.
Sherlock tried to think of something clever and cutting to say in response, but in the end he could only return John's infectious grin. Some of the tension in the room eased, and he felt his shoulders relax.
"It'll wash," Sherlock said.
They grinned a moment longer, until Sherlock remembered his very obvious erection. The memory brought a flush to his cheeks, which discomfited him still further, and he turned away, swinging his feet off the edge of the bed onto the floor and preparing to leave.
He would have to take care of it alone. Two times in one night, a first, an absolutely unprecedented event. At least now, Sherlock realized, he had the mental material necessary to stimulate himself. John's hot wet mouth centimeters from his, the sound and sight of John's orgasm, the curious thrill of a bumped head and being used roughly for another's pleasure. The night had not been wasted, if only to collect this useful information.
He looked back over his shoulder at John, who was regarding him with a heavy-lidded intensity.
"Have a good sleep."
A shiver went through Sherlock as he read John's other meaning -- John knew what he was going into his own room to do, John knew what Sherlock would be thinking about, and Sherlock knew that John knew and it was all a closed circuit of arousal and response, intimate and overwhelming -- and then John smiled.
"Good night," said Sherlock, and fled.