Co-written with starrysummernights. This fic was originally under her pen-name, but in order to keep up with the updates, we decided to shift it onto my page :P This is part of the 50 Reasons to Have Sex Prompt, and will therefore be quite a long one! Please enjoy, all feedback is welcome and appreciated, and will make us do happy dances :3

1 - Because you can't get to sleep

The door to John's bedroom softly swung open and a tall, wraith-like figure slipped inside, shutting the door behind it with a barely discernible click. On the bed, John made a sleepy sound of distress, throwing one arm outside his covers. The dark figure froze, its entire body stiffening. It silently watched John thrash on the bed before he settled, dropping back to sleep again.

Across the room, Sherlock breathed a sigh of relief, his heart pounding in his chest at the fear of discovery, at being in John's room while the other man slept. He knew this was a bit not good...but was unable to help himself.

A slightly chilly draft insinuated its way into John's room from the open window, causing the older man to twitch his exposed arm vaguely. The previous, record-breaking heat of the spring day had rapidly collapsed into a cool, starless night and the open window provided an enchanting, cool tang of London midnight air, tasting of pollution and the residual sweat of a working day. The cool air swirled in the room, mixing into a delectable cocktail with the sleep-tainted, mouth-watering musk that was John Watson.

Breathing deeply but softly, Sherlock moved quietly towards his...towards John's bed, kneeling carefully at the side, his knees making the barest of thunks as he lowered himself to the floor.

His eyes, keen even in the dark, roamed over John's supine body, frustratingly shielded from his sight by the sheet. Sherlock wanted to touch, wanted to reach out and run his fingers along John's exposed skin, feel the heat of his skin and the softness of John's fine hairs beneath his fingertips... But then John would wake up. He'd blink sleepy eyes up at Sherlock, at first bemused by his presence…before frowning. He'd get angry, demand to know what the hell Sherlock was doing in his room at almost midnight.

Or would he?

Sherlock sucked in a sharp, excited breath and reached down, squeezing his firming cock through his pyjamas. Instead of getting angry, would John maybe smile? Give Sherlock a lazy, seductive grin and pull back the covers, invite Sherlock into bed with him? Would he kiss Sherlock- not the chaste pecks Sherlock was already addicted to- but kiss him properly, with lots of tongues and saliva and heat?

Sherlock glanced up, rather resentfully, at John's wide-open bedroom window, which was inviting the occasional moon-chilled breezes inside, birthing goosebumps on the sleeping doctor's arms even as Sherlock watched, his pale grey-green eyes aided only by the sickly-yellow, feeble streetlights at the end of Baker Street.

He wanted to close the window but was afraid the noise would wake John. And that was something Sherlock wanted to avoid. Desperately wanted to avoid.

He knew he shouldn't be in John's room without permission...but he wanted...he wanted more.

He and John had officially been dating for a week.

The past seven days had been the happiest and yet most frustrating ones of Sherlock's entire life. He'd thought, once he and John got together, that John would be more...ardent. More randy than he actually was with Sherlock. All Sherlock's data about John's past girlfriends suggested John would be trying to have sex with him after the very first day- and Sherlock had been eagerly, if a bit apprehensively, looking forward to it.

But John hadn't even hinted at moving things beyond the too-quick pecks he sometimes gave Sherlock, innocently pressing their lips together before quickly pulling away. They'd talked, endlessly dull conversations in which John had asked Sherlock about his past, how many people he'd kissed (zero), how many people he'd slept with (again, zero), and how many he'd been attracted to (a very low number which had made John frown). Sherlock's virginity obviously made John want to take things slow and Sherlock, for one, was tired of it.

Licking his heart-shaped lips, a rogue spring breeze almost immediately cooling and drying them, Sherlock took a few deliberately slow breaths and very gingerly inserted his long-fingered right hand into his pyjama bottoms. He gulped irrepressibly as he touched himself, wincing with a mixture of distaste and arousal as his fingers and thumb detected his own warm, slick, traces of pre-come.

He rubbed experimentally at the wetness, absently slicking it around the exposed head of his cock-

Sherlock gasped at the unexpectedly pleasurable lightning bolt of feeling the action elicited. It speared its way through his abdomen and ricocheted back to settle, throbbing and hot, in his testicles. Sherlock's' cock bounced in his fingers, blood pumping hotly through it, and he bit his lip to keep any more rogue noises in.

He didn't want to wake John.

Slowly, mindful of making too much noise, Sherlock began a deliberate, firm rhythm at his cock, pumping his hand over the swollen shaft with brisk, business-like strokes designed to get him off in a hurry. He hadn't done this in ages- hadn't felt the need- but since his and John's first kiss, Sherlock's libido, usually quiescent and dormant, had taken a sudden upswing. It'd clambered for his attention on a daily basis, whereas before he'd barely felt the occasional twitch. It was incredibly distracting. Tonight, he hadn't been able to sleep for his erection, his mind conjuring up the most lascivious fantasies involving things he and John could do together…if only John would be amenable.

Sherlock closed his eyes, losing himself in the tingling sensations he was provoking in his own body. The fabric of his pyjamas rubbed distractingly over the head of his cock with each motion of his hand, brushing along the sensitive skin and making Sherlock shudder in increasing desire. He nibbled on his plump bottom lip, grimacing in pleasure, eyes still tightly closed. It was a risk he was well aware of- John could wake at any moment and catch Sherlock unaware- but he couldn't resist as his strong fingers continued to tease and tug on his tumescent shaft. Sherlock's staggered inhales, growing heavier the faster he moved his hand, tasted of John's sweet, sleeping, nocturnal, delicious, irresistible scent...Sherlock choked down a lustful growl as the sexual adjectives regarding his doctor- of which he had many- began to spin and mount into lascivious stacks and engage in vivid, flesh-coloured orgies in his Mind Palace.

He opened his eyes, staring at John's sleeping form laid out on the bed, still and quiet and unaware of what Sherlock was doing. For how much longer? How much time did he have before John woke? He had to finish this- now- before John came awake. Heart pounding, Sherlock sped up the motions of his hand, face feeling hot as he stifled his heavy breathing. He was afraid if he opened his mouth and breathed properly he'd wake John…and this would all be over. He didn't want it to be over. He didn't want John to get angry with him, or be forced to go back downstairs to his own room and finish himself off alone, in the dark, without John. It was much better here, listening to John breathe, knowing he was just an arms-length away…

Sherlock, feeling the gravity of the situation, stroked faster at his cock, urging himself to come-….come-

John suddenly shifted on the bed, body moving restlessly beneath the sheets, and Sherlock went instantly still.

His cock, gripped in his hand, pulsed, adrenaline surging through his veins. A thin string of pre-come welled from the tip, dribbling along his fingers as he held his breath, heart in his throat, watching John writhe.

Sherlock ached to move. His cock throbbed in heated arousal and he could feel himself poised on the very brink. He was afraid to move, afraid to give in to the overwhelming desire to finish himself off, afraid the smallest noise would wake an already fidgety John. And so he remained kneeling beside the bed, cock hard and leaking in his hand, holding his breath, waiting for John to settle again.

To Sherlock, mouth dry in arousal and fear, it seemed to take much longer than it should have.

Finally, once he was sure John was asleep, his breaths once again even and deep, Sherlock huffed in abject relief. He began furiously moving his hand over his cock, desperately needing to come. His hips twitched up into his hand and he grunted as softly as he could as he felt the first, faint stirrings of his orgasm looming.

Sherlock very slowly eased himself back from the bed's edge, where he had been soaking up John's unconscious sighs like a perverted sponge, and watched the minuscule hitches of breath expounded by John's lungs and expressed in the rise and fall of his chest.

Sherlock's eyes slid almost shut, his mouth falling open in a soundless cry of pleasure. Quiet, quiet, quiet! His mind shouted at him, and he was trying. He was trying so very hard, even as his orgasm threatened to crest, singing along his nerve endings like fire and making him want to shout. He dizzily realized he had nothing to catch the result of his pleasure in and gave his pyjamas the briefest, irrational apologetic glance in the gloom of the barely lit room.

John stirred again, turning onto his back and throwing his head back, revealing the strained line of his neck.

Sherlock choked, gasped, unable to stop himself, not when he was so close- he couldn't stop-

"Mmmm..." John moaned sleepily. It was a sound of contentment at finding just the right spot to lay or a really good dream getting even better…but regardless of the reason, the sound went straight to Sherlock's cock.

"Oh!...F-fuck!" Sherlock forced out, losing his balance and helplessly tumbling back against the radiator, his body hitting it with a loud CLANG. He gritted his teeth and tried his utmost to hold back the desperate, breathy yelps that burned up his throat as his body trembled through the orgasmic shocks of previously unknown intensity. The sharp lance of pain in his upper arm translated as the merest whisper in his head under the paralyzing weight of his climax. Sherlock's entire body was trembling, pleasure zinging through his frame. His brain felt fried.

As the last of his orgasm faded, Sherlock, quietly panting, stared at John in dread, knowing he'd been too loud. He waited for his new boyfriend to wake up and discover him there- on his arse on the floor, his hand still wrapped stickily around his cock, his crotch covered in come.

John, though, slept on, unaware of what had happened.

Sherlock breathed a huge sigh of relief.

Swallowing heavily, his chest heaving and limbs trembling, Sherlock wiped his hands ineffectually on pyjama bottoms that covered shaky thighs. He inhaled a few more much needed breaths, his body reluctantly coming down from its orgasmic high, wincing at the feeling of lukewarm semen gluing itself unpleasantly to his crotch and upper thighs. Sherlock stood with a stifled groan, his muscles protesting the movement, his legs having fallen asleep as he knelt beside John's bed.

He allowed himself a brief glance at John, wishing he could just clean up and snuggle in alongside him and share in his languidness. Have John sling an arm around his body and share his heat. Sherlock had never woken up beside anyone before, he'd never even slept with someone, and he wondered what it would be like. Uncomfortable? Crowded? Strangely erotic? Stiflingly hot?

John had made himself very clear, though, on more than one occasion: he thought they should be taking things slow. Unhurried at an almost glacial pace. Sherlock smiled fondly but exasperatedly at his sleeping John. He was grateful John was the way he was...but he didn't want to move as slow as John was suggesting.

Heaving another sigh, he turned to go, walking on tiptoe to the door and carefully opening it. He slipped out without another sound, closing the door and creeping down the stairs, wincing at the way his drying semen painfully pulled at his pubic hairs.

After Sherlock's footsteps - heavier than he'd like to believe, despite all his claims of being a master of stealth (and, when he was drunk, "A... SUPER ninja John! Like...a cartoon...like those...tortoises...") disappeared downstairs, John allowed himself to grin in the dark, hugging his pillow to himself.

He chuckled and reached between his legs, his own cock hard from listening to Sherlock's impromptu wank session. Still grinning, he began jacking himself hurriedly, breathing heavily. He'd woken when Sherlock had opened the door but pretended to sleep, wanting to know what his new, irrepressibly curious boyfriend would do. John had been shocked- shocked to his core- when he'd realized Sherlock was wanking, was touching himself stealthily in the dark beside his bed…

"Oh." John breathed, replaying the way Sherlock had reacted to his staged moan, the way Sherlock had gasped and cursed through his own orgasm, unable to stay silent. Fisting himself harder, John wasted no time in bringing himself to a spectacular orgasm, sinking back onto the bed in relief. He grinned into the dark, shaking his head. It seemed he needed to have a talk with Sherlock in the morning.