There are not words for the rage i feel at having to wait for a new series. So i'm filling the gap with writing :)

They had been doing this for months now. It started as an idea in the back of his head, and it niggled away at him until he had to pay attention. A case involving Irene Adler again, and all the sexual implications that meant. Sherlock had to admit he was at a disadvantage with that women only because of his inability to understand anything regarding sex. So he had played with the idea in his head, tossed it around and looked at it from every angle. The only solution it seemed was to learn, and in his experience, one learnt by doing.

The question was who. And the solution had presented its self beautifully in the form of one John Watson. He was loyal, stable, a good friend. He cared and he was excellent at keeping secrets. There was the small problem of his constant denial of homosexuality, but since Sherlock had known from the moment he met him he wasn't straight that didn't matter. So he had asked, straight faced and without a hint of embarrassment or shame. He had sat across from his best friend, his only friend and had clinically explained,

"I need to understand sex, I want to know why it drives people to do such stupid things and how it can be used as a method of control. So I propose we have sex and I can catalogue the results"

John had walked out of the flat without a word and didn't return for several hours.

In hindsight (talking with John afterwards) it wasn't the best way to approach the subject. Although as Sherlock still liked to point out; it had worked. John had scowled at him and then smiled softly,

"I suppose being one of your experiments is a fairly high compliment"

Sherlock lay back in what was fast becoming their bed, cigarette dangling from one finger as he listened to John move around the bathroom cleaning up. The habit was highly convenient, for one it gave him the chance to have a smoke without John knowing, and secondly he could let the event mull over in his mind without distractions. John had been surprised that Sherlock didn't immediately dash into the shower, the usually fastidious man seemed completely unbothered by the layer of cooling sweat across his body, amongst other things. But Sherlock had found he actually enjoyed laying in the rumpled and dirty sheets, for a time anyway. Once John had finished he would of course wash briefly before climbing back into the sheets. But the first reaction he had catalogued was the complete lack of desire to do anything but lay and bask in the after glow, he was mildly disappointed John didn't want to either, but he supposed he could always ask him to stay next time.

It was an odd sort of high, nothing compared to the haze of his drug usage, but it did have that all important fuzzy dullness that he had been seeking when he started using. But more importantly it didn't come with a complete loss of control and the inevitable down. Plus this was legal, mostly.

He considered telling John he was his new drug, a new addiction. But he wasn't sure that would go down to well, nor did he want to discuss his drug habit with the doctor. Another startling result of this experiment was the emotional response he was having. Something he had not counted on, he had always assumed it would be easy to separate physical from emotional. Maybe it was because it was John to start with he reasoned, but since this experiment had started he found himself worrying more and more about the doctor, worrying about if he was happy, if this was OK. He never asked, just in case John said no and wanted to stop, he might worry but he was still as selfish as ever.

The first time had been odd, he supposed, he was only going on John's behaviour never having had anything to compare to. But the nervousness and suddenly awkward behaviour had indicated John was not comfortable. He wondered if that was normal, so he had asked and John had fixed him with that look he had that showed Sherlock he had said something stupid. Sherlock hated that look.

"Of course this isn't normal, this is not how two normal people get together, they do not have a clinical discussion and set a time and a place. God, I can't even believe I agreed to this" and John had left, again. And Sherlock had wondered if it was normal to feel so empty. He wondered if it was normal to feel his stomach cramp uncomfortably when John walked back into the flat several hours later. He stopped wondering anything at all after surprisingly strong arms grabbed his collar and dragged him to his feet, chapped lips pushing at each other, without any care for finesse or technique.

So their first time was odd, Sherlock was confused and John was angry, and frustrated. They'd talked it over a few weeks later when everything was less…odd. John had walked around London for hours, refusing to think about it, before realising that is all he had been doing for months. Thinking about Sherlock, every little tiny thing he did, it wasn't even sexual it was just all consuming. He had stopped, somewhere on the Southbank and stared out into the river before laughing softly to himself and hailing a cab home. Of course this wasn't normal, but that's why his thoughts focussed on Sherlock, he loved every single second of the abnormality. He had intended to come home and explain this, to rationalise it the way Sherlock would have wanted, could have understood. Instead he came home and saw him sitting in his chair, waiting, a sad little look on his face like he half expected to be waiting forever. John had forgotten everything he intended to say and had just had the strangest urge to grab the taller man. So he had. He still blames Sherlock for putting the idea in his head in the first place. It's a blame Sherlock is willing to take.

He didn't really get much data from their first time, it was too much of a surprise. He was too caught up in the moment, with so much happening at once it was hard to take it all in and make sense of it. John caught him trying to think almost immediately and had slapped him sharply on his behind. The sting of it sent an odd thrill through him. People rarely touched him and never with such authority, he had groaned at that point, and his brain registered the unfamiliar sound, but John whispering in his ear meant any deductions stopped right then,

"No, Sherlock" he wondered when John's voice had got so rough "not here, you're here to learn, and you learn by doing not by thinking. For once turn off, or I'll smack you again"

There was that sound again, escaping his own lips without permission and John smirked against his ear. Roughened hands had trailed their way along his body, swiftly divesting him of clothing and pushing him back against the sheets. It had passed in a blur, one long, beautifully mixed up blur, for the first time Sherlock found he couldn't recall each detail with perfect clarity, and at the same time he couldn't manually delete them. Snatches of it came unbidden to his mind at the most awkward of times for days afterwards.

Sherlock had laid there, spread out with no shame whatsoever, breathing heavily trying to make everything make sense again. John supposed he was unaffected by the nakedness of the moment (both literally and figuratively) because he was too busy cataloguing data and drawing conclusions,

"So, what deductions have you made?" he asked when he exited the bathroom, unsure whether to feel used or just go with the moment and enjoy the physical release he hadn't had in a while, he was used to sleeping with women, who usually required some kind of emotional attachment, or at least a date first. He wasn't quite sure what the protocol for sleeping with your flatmate so he could try and turn sex into a science was. For once Sherlock did not have a series of observations or a smart remark to come back with, he had simply looked over at John and with a childlike grin that disconcerted John for so many reasons,

"I had no idea it would be nice"

John had stared at him for a few seconds before laughing and sitting on the edge of the bed

"Well, what were you expecting? Of course it's nice or people wouldn't do it"

Sherlock had hmphed and frowned before flipping onto his side; sulking. He didn't like it when he found something someone else knew better than him. John had sighed and slid a hand along a pale shoulder squeezing gently, unsure of how to continue, after all this was his bed, Sherlock showed no signs of moving, and he sure as hell wasn't sleeping someone else. He almost laughed at how ridiculous it was, he had had sex with the man and was now faffing about deciding whether or not it was ok to sleep with him. He patted the shoulder gently,

"It's ok to not know things Sherlock, it's how everyone learns" he had murmured slipping beneath the sheets. His hand receding as he felt no response from the other man, thin cold fingers grasped at his just before they left and pulled him in closer wrapping John around himself like a blanket Sherlock offered no apologies or thanks, just nibbled gently at the tip of one finger in what John assumes he thinks is adorable. Or maybe he's just hungry, you never can tell.

Nothing changes, they get up, the wash they dress and John goes to work. Sherlock gets bored and puts more holes into the wall. Lestrade and Mycroft bombard them with questions and requests for help, Sherlock ignores them and gets more and more bored and more and more holes appear. John isn't even sure where he's getting the guns from anymore and has given up trying to find out.

It's Sherlock who snaps first, who declares their first experiment null and void, because it wasn't done in a controlled manner. John resists the urge to point out that's the entire point, and pointedly ignores the twist in his stomach at the thought of sex with Sherlock again. He'd been refusing to mention it, refusing to talk to Sherlock and admit he enjoyed it, he wanted more. He assumed, and hoped Sherlock would be happy with what he had already learned. Or at least distracted enough to forget about it.

But as Sherlock called out from his bedroom, he found his feet betrayed him as they followed. He finds it amazing how that imperious tone remains even though he can tell Sherlock is nervous.

So they began their second time, and Sherlock took control, he was a quick study and had evidently discovered sex can be learnt through books. At least partially. John could see him murmuring to himself as he noted all the feelings and reactions of his body and John's and he smiled, it was entirely Sherlock, studying something and knowing it entirely made him comfortable with it. John was glad it was him he felt comfortable with.

Afterwards Sherlock goes through his deductions, he catalogues physical responses, chemically induced reactions, he lists his own emotional responses and the ones he observed on John. He notes the good doctor is not as uncomfortable engaging in homosexual sex as his words of protest had first suggested and John kicks him. He drifts off to sleep listening to Sherlock excitedly talk about their sex life as if it were a case or a specimen in a lab. He smiles, amused that they even have a sex life to discuss.

Sherlock demands another experiments a few days later, to get sufficient data to make consistent statements of fact he says. Then a few days after that, the excuses get more and more flimsy until one morning when John wakes to find Sherlock piling his clothes into his wardrobe,

"I spend most of my time here anyway" he says "Neither of us are stupid, we both know my reasons behind continuing this are no longer strictly scientific"

And John finds himself with a boyfriend? Partner? Lover? No he thinks, I have a Sherlock, my Sherlock. And that really is the only way anyone can define any relationship they have with the man.

And any doubts he has about Sherlock's emotional attachment is banished when he gets a birthday card (two weeks late, but still) inscribed with the detectives swirly writing 'To my best experiment yet, 'You learn by doing.' I want to learn about you' It wasn't exactly I love you. But it's about as close as Sherlock can get.

I am not certain about the characterisation here...I have been reading to many fics where Sherlock is sort of childish and innocent in regards to sex. which IS cute and nice to read. but on the whole inaccurate i feel its just not in his character to be innocent and sweet about anything. so ive rewriten this a few times to see if i can get as much cutesey out of Sherlock as possible. :S