Work Text:
Choquet integrals (see The Transposable Choquet Integral) are said to have the quality of “maximum cooperation.” That is, when performing such an integral, one starts out with all the members of a set together, and then continues on as they “leave” (think of workers in a factory, all put into the same room to cooperate with one another). Lebesgue integrals (see Blood, Sex, and Lebesgue Integrals), on the other hand, are said to have “minimum cooperation.” In this case, each member of the set is separated from the others (think of workers in a factory all put into separate rooms to do their work) because in the Lebesgue integral, not only are the “cuts” formed horizontally, as in the Choquet integral, but also vertically (it is a special case of the Choquet integral).
***
John shouldn’t be doing this.
It is pretty damned high up on the list of the top fifty things that it would be Very Not Good for Flatmates to Do, and that was impressive, considering the majority of the list was constructed with Sherlock in mind.
But it was borne of concern, really. At some point in the past few months, something had changed. He and Sherlock went off to their separate rooms, unfailingly. No dozing off in armchairs or accidentally winding up piled atop each other on the sofa. No coming downstairs to see that Sherlock had fallen asleep at the kitchen table; no being prodded awake by Sherlock’s curious toes from the spot on the floor that had seemed comfy after he’d gone drinking the previous night.
John knew why he had started going to his room. Sherlock’s reasoning, though, had to be different. He was doing something else there, conducting an experiment or observing the habits of the neighbors or waiting for something to boil over in the kitchen and creeping back out in the middle of the night to check on it. John had thought, for a time, that Sherlock was just following suit with John’s activities, for whatever reason, and tried staying up later, but at eleven p.m. Sherlock consistently retired to his room. John had even asked him why, once.
“Nothing here to do, I suppose,” Sherlock answered, some variety of frustration or weariness creeping into his tone. “May as well get some rest.”
But Sherlock didn’t sleep. Well, of course he did, but not like a normal person. He mostly took naps. John had almost always already been asleep when Sherlock went to bed, but he suspected most nights Sherlock rested for four hours and called it good enough.
Which meant he was spending some time in his room doing something else.
John spent his time doing something else, too. He hadn’t even put two and two together at first, that a few things had led to his change in schedule. They were just a couple of freely floating facts about his life—somewhere along the line, he had become attracted to Sherlock. It surprised him, to say the least, and he spent hours and hours trying to justify it until he realized that it was stupid, all stupid, because he actually didn’t have to justify a single damn thing to anyone. He doubted anyone even cared that much. So he let go, and let himself enjoy it. Well: as much as he could, constantly sitting across from Sherlock or standing beside him or crouching near him, always looking, never touching. He stopped trying to think about ex-girlfriends when there was really only one person who held his interest—even when he partook of his nearly nightly wank. It was—freeing. But it also meant that he started to pay more attention, more and more attention, to softly parted lips with lovely arches, a bobbing Adam’s apple, keeping time with a voice that shook his bones (and shook his bones), skin and muscle and skin that needed to be touched. It meant that staring across the room at Sherlock, or sharing a sofa with Sherlock, and falling asleep on Sherlock, became markedly more difficult to handle appropriately. But he was John Watson and he was a good flatmate, and he kept his business to himself and simply retired a little bit early before he said something too terribly stupid to Sherlock about his eyes.
And so Sherlock’s whereabouts in response were a mystery. But not for much longer.
Of course it was a bad idea. Sherlock would probably notice—he would almost certainly notice. But perhaps he kept the lights dim, or perhaps something else kept him occupied. Surely he didn’t thoroughly check his room every night before he went to bed?
This was Very Very Very Not Good.
And maybe just asking would’ve been the way to go, but what was John supposed to say, “Oh, good morning Sherlock, say, last night when you went to bed about eleven even though you can’t possibly fall asleep any earlier than three on any given night, did you spend that extra time having a wank? Oh? Were you thinking about me? Well that’s just lovely. Fantastic to know. Thanks.”
Of course he wasn’t going to be so intrusive as to use a camera—god, no. This wasn’t really—well, it wasn’t terribly different from pressing an ear to the door, was it? It was just a microphone. John wouldn’t have to feel like he was intruding on Sherlock’s privacy if he saw him in his skivvies (not that Sherlock would care, probably; he wore nothing but a sheet to Buckingham Palace, after all), or in—less. With sound, all he could make were inferences.
John made sure his headphones were plugged securely into his laptop and placed the buds in his ears. Sherlock would be entering his room at any moment.
And so he did.
John heard the faint rustling of blankets being rearranged, a few sounds that might have amounted to clothes being thrown onto the floor. It was more obvious when Sherlock flopped down onto the bed, a puff of air blowing over the microphone. John had secured it to the side of the mattress, at the head of the bed. It was perfectly possible that he wouldn’t be able to hear much of anything this way; he’d hidden it under the sheet somewhat, and of course if Sherlock just laid there, or was especially quiet at—
“Ngh,” startled John very suddenly out of his thoughts. Maybe Sherlock had just pulled a muscle, though, perfectly—“Christ,” came a whisper.
John felt his hand meander to his own pants and then beneath them. Maybe this was nothing like what it sounded like, but John could perfectly imagine Sherlock there, the chaotic center of his perfectly tidy bedroom, sprawled out over the top of the coverlet, probably entirely naked. His head would be nestled into one of those stupidly comfortable pillows that were a complete waste for someone who slept as little as Sherlock did, his loose curls tossed around him like a messy, dark halo. There would be another of those, too, another dark halo, John thought—farther down, a nest of hair nestled around Sherlock’s penis, and John hadn’t decided yet what it would look like, always changed it when he laid down with his imagination. The idea of Sherlock and sexuality still strained John’s mind—so he envisioned that Sherlock would have to lie there for a while, acclimate to his surroundings and his nudity and the idea of what he was about to do. But however difficult John found it to imagine it, it was statistically very likely Sherlock did.
So Sherlock would gather himself, take a few deep breaths, snake his long fingers down his body to acclimate himself further, to get used to the idea of touching—first his face, common easy; neck, more vulnerable—he would spread his hand out over his chest, feel his heart picking up speed. Maybe, John thought, if he was feeling particularly daring, one of those spindly fingers would stretch to a nipple and circle around it, prodding, touching, investigating. He’d move down his belly, maybe leaving his fingers to hang over his side, feeling ridges of ribs and almost tickling him, and then finding themselves winding up naturally in the groove, the crease, the outline of his lower abdominals leading naturally to his only slightly hardened cock.
From the microphone, John heard silence. Breathing. Shifting.
Of course, he wouldn’t just touch himself then. He’d have to continue on, inner thighs, however far his fingers could reach, before working his way back up.
John swore he’d heard a sharp intake of breath. Of course, it could be anything.
He would start slowly and gently, and perhaps begin conjuring up mental images. A comforting somebody else who was there with him, stroking his cheek or running unassuming hands over his body.
Maybe, eventually, he would find a rhythm. Maybe sometimes he didn’t. Maybe sometimes he just stopped and breathed, breathed, came down, left it be, and dozed off. Maybe it took him several days to work up to it. Maybe it didn’t: maybe he knew exactly what he wanted. Maybe he demanded it, fingers clinging to the bedsheets and toes curling, head twisting as he directed himself efficiently toward that glowing point of heat, huffing out breaths. John grabbed himself at the thought, stroked absently until his mind locked onto the pace, and then there was no—
From John’s headphones, the noise started softly—a light flicking in the background, like Sherlock had discovered a loose piece on the bed and couldn’t let it be. But then it continued, and it was steady, and determined, more slapping and less flicking, and accompanied by quicker breaths. John took in a shaky gasp when he realized he was keeping time with the sound, that maybe right at this very moment, each in their own separate rooms, he and Sherlock were—
“Hello, John.” The cheap microphone failed to capture the lower portions of Sherlock’s voice; John startled and nearly knocked his laptop off the bed. “Is this helping you? Shall I move closer? Here.” From the sound of it, he had found the microphone and was lifting it from its spot. John remained frozen.
John remained frozen until the slapping resumed, but more loudly. Much more loudly. Right—oh, oh god, and John, without thinking about it for a second, had his hand back against his erection, pumping it in time to the sounds, so loud because the microphone was right there and Sherlock had found it and put it there and, “Oh, god,” John groaned.
“Would you like to know what I’m thinking about, John?” came Sherlock’s voice from farther off, from over the hills of his torso and the valley of his throat. John nodded, and failed to feel even the slightest bit stupid about it, exhaling breath that he’d apparently been holding through lips that shook slightly as it escaped.
“I’m guessing that when you retire to bed to have a wank, John, you methodically remove your clothing first. You peel back your covers and climb in. And then you’re right there, John—oh, maybe you tease yourself a little, but you’re palming yourself in no time.” A pause, broken by slightly labored breaths. The microphone seemed to be shifting, slightly closer to Sherlock’s voice, perhaps so John could better hear him. “You run a hand through your hair, allow yourself a little indulgent back-arching. Don’t you?” John felt his back arch at the words. “You don’t need a setup. You don’t need a plot. You conjure thoughts spontaneously, abstractly: someone’s legs you wanted to grab; someone’s throat you’d like to touch. You’d like to touch my throat, wouldn’t you?”
“Sher…” John groaned, because god, god yes, yes, he very much did want to do that.
“Is your door unlocked, John?” Sherlock asked, and John shivered.
“Yeah,” he muttered, not that Sherlock could hear him, because—
The door swung open.
“It occurs to me this entire process might be more effective if we worked together,” he said, and, John thought, those words were far more arousing than they had any right to be. “May I come in?”
John could only nod. He set his laptop on the nightstand and guiltily pulled his hand from his pants. (Sherlock hadn’t gotten everything right, of course—still, not a bad guess.)
“No, put it back,” Sherlock said. He dropped the microphone on the inside of the doorway as he closed John’s door behind him. “Let me watch you, John.”
“You, too, then,” he sputtered. “Come here.”
Sherlock sat on the edge of the bed and then laid down when John scooted over. He gave John a searching look. “I’m not entirely certain I thought this through,” he muttered. “I want to watch you but you probably want to…ah…”
“Watch you, yeah,” John breathed, leaning closer than he thought he’d ever be able to. He licked his lips, steeled himself, and leaned forward to kiss Sherlock’s neck. Sherlock shuddered beneath him. “We could help each other out,” he suggested. Maybe—maybe Sherlock had never done anything but— “If you don’t want to touch yourself while I’m—then I could—if you want—”
“Oh,” Sherlock said, as if it were a grand revelation at a crime scene. He tentatively took John’s hand in his and then laid it on his softened erection, staring intently. “Yes, that’s—that’s not so bad. Then could I…” he reached for John’s midsection.
“Yes,” John said, “oh, god, y—yes, Sherlock. Christ. Please.” It would probably be too much, too soon, but— He shuddered as the warmth of Sherlock’s hand closed over him from outside his pants, and couldn’t stifle a groan as Sherlock’s fingers tentatively wriggled underneath them. “Here, let me…” he reached down to pull them off.
“I’m not sure our arms will…” Sherlock started, indicating the orientation of their limbs. “We’ll bump into each other and…”
“Fair point,” John said, and his tongue poked out from between his lips as he thought.
“I do think of you, John,” Sherlock said after the prolonged silence. “When I masturbate.”
John felt himself flush. “Um, yes, well—me too. Of you.”
“Roll on top of me,” Sherlock said. “I’ve an idea.”
“Right,” John knelt over him, trying not to succumb to the sudden dizziness of looking down and seeing Sherlock sprawled out nearly naked on his bed below him. He lowered himself gradually and braced himself on a forearm on either side of Sherlock’s chest. “Like this?”
“And now I…” Sherlock reached down and pulled his pants down around his legs. He used one hand to push John’s lower back so that their midsections were closer together, and the other hand slithered down between them and oh, and oh oh oh,
“Oh, god.”
Sherlock’s hand wrapped around the both of them, and between the press of his fingers and the heat of another hardening cock beside his, John felt himself begin to swell up again, and Sherlock groaned, and what more perfect hands than his for this? John recognized the progression, recognized the pacing, from over the microphone only—god, could that be minutes?—ago, Sherlock seeking what he needed, picking up speed, gripping them tighter. “John,” Sherlock mouthed, and brought one hand to John’s hair, and twisted it in, and John couldn’t restrain a guttural sound.
“Jesus, Sherlock,” John managed through clenched teeth. He wouldn’t be much longer, not like this, overstimulated by so much Sherlock around him, touching him, getting him off. “You’re gonna have to bloody slow down if you want this to last much longer, I…”
“No,” Sherlock said, nearly barked, and then his voice dropped to quieter tones, a chanted mantra, “I need it, John, I need it, I need it…” His hand sped in time with the words; his grip in John’s hair tightened, and soon he was clutching John’s head to the crook of his neck, back arching, choking and gasping to pull air in and then whimpering it back out. When his grip loosened John growled and reached down himself, grabbing his own erection and giving it several firm strokes more before releasing, oh god, all over Sherlock’s skin. He sucked in a few shaky breaths, raising his eyebrows at Sherlock.
Sherlock gave him a lopsided smirk, and John let loose a series of high-pitched giggles, shaking his nerves out.
“That was much more enjoyable than the alternative,” Sherlock said tentatively as John rolled off of Sherlock and collapsed onto his bed. He grabbed a corner of John’s sheet and made a halfhearted attempt at wiping off his belly.
“Same time tomorrow?” John asked.
“I suppose it could be arranged.” He turned onto his side. “John—in light of recent data—I was wondering if—well. It just may be possible that—”
“Out with it, Sherlock,” John sighed.
“Well, it appears our cooperation and mutual presence is beneficial in more scenarios than I had originally expected, and I was thinking that the realm of other yet-untested areas includes sleep—and while of course I could just as soon—you may want to—”
“Shut up and go to sleep, Sherlock,” John tucked the sheet and comforter over him, turning the lamp off and resting one hand tentatively against Sherlock’s shoulder as he rolled onto his belly.
Sherlock laid his cheek against John’s hand. “Collecting data,” he mumbled as he drifted off to sleep.