Warnings: M/M slash, don't like don't read. Non-explicit sex. Suggested curse.

Disclaimer: If I owned Sherlock, I would be making the third season get on television already.

A/N: As fellow author Lyricoloratura said when she posted her first Sherlock fic, all those lovely people who have set me on author alert for my Star Trek and Harry Potter stuff must be wondering what I am doing writing Sherlock stuff. I haven't forgotten about my other fandoms, promise.

Okay, I wrote half of this before watching The Reichenbach Fall, and so you can stick with the first chapter, and you get a love story with spoilers through The Hounds of Baskerville, or you can read both, and you get a tragedy with spoilers through Reichenbach. Your choice. I honestly didn't know whether I should end it before Reichenbach or not.

It had been a bit of a shock for Sherlock to realize that he cared about John.

You couldn't help but respect a man who had, steady-handed, shot someone dead to save your life, especially as that man hadn't been Mycroft, or even Lestrade or some other acquaintance, but his new flatmate, who'd known him for practically no time at all and still thought he was worth saving.

Respect was one thing. But then there was the time he had told John to take his opinions elsewhere, and for once in his life, he'd not only realized he'd hurt the man, but cared enough to try and make up for it. And when he said that he never cared about his clients, the look of disappointment, that hurt.

Sherlock Holmes wasn't used to wanting anybody's approval.

Especially that of someone like John.

It was one thing to match wits with the serial killer cabbie, or Irene Adler, dazzling intellects almost as good as his own. But John, who was so perfectly ordinary, or perfectly average IQ?

But he wasn't entirely average. Mrs. Hudson had pointed out that of the quirks one ought to know about in a flatmate, playing the violin at all hours certainly rated, but keeping severed heads in the refrigerator ought to rate higher. And it had taken only days for John to acclimate himself to the habit. Plenty of other men, Sherlock might even hypothesize most to all other men, would have had to know him for a significantly longer time before being able to look up as he came in covered with blood spatter and remark only that he must have made a sight on the train. Sherlock wondered if he ought to try it again that time next year, just to see if John was used to him enough to merely inquire as to whether he'd remembered to buy sugar.

And John hadn't given up on him yet.

All his life, Sherlock had come to the same conclusion: sentiment only gets people killed. After Irene Adler, he'd reaffirmed his conclusion, something he'd been beginning, just slightly, to doubt, in light of his friendship with John. How good it felt, to have a friend. And yet, he ran after John after leading him to the conclusion that Sherlock did not consider him a friend. He'd had an idea that some distance between hem would be better, but found he couldn't bear the pain, of the look on John's face or of the thought of losing what they had.

Sherlock had known he was gay for a very long time, but before, it had always been entirely physical. He was attracted to men's bodies. That was all. Never had he had the slightest romantic inclination. John, on the other hand, watched him as though enjoying the sight of his body, muttered things about cheekbones in a flash of anger, and yet continued to correct the vast number of people who assumed they were a couple.

Until he stopped. Sherlock noted it, as he noted everything. The bartender, only the latest in the line, had made some comment assuming they were lovers—and John had not bothered to correct him. He had started to, and then he had stopped.

Sherlock wanted to know why. Was it because John was simply tired of correcting people? Or did he like the idea?

Sherlock, had, of course, heard of the notion of friends with benefits. John was attractive, and Sherlock liked him. That was all. He could not allow there to be more. But the attraction, if John wanted, could be acted upon.

Soon after the case of H.O.U.N.D. and Baskerville, Sherlock was in another one of his antsy moods. He always felt withdrawal when he didn't have a case to occupy him.

"You know, when normal people get this tense, they have sex," John remarked in exasperation, trying, Sherlock expected, to distract him from his search for nicotine. What Sherlock believed John hadn't expected, was for Sherlock to stop and consider the idea.

Contrary to popular opinion, he wasn't a virgin. However, he drove most potential partners, even those just looking for a quick shag, away by telling them their life story. The only one he hadn't deterred had been too drunk to listen, and, in fact, so drunk that Sherlock had decided he preferred pornography and his own vivid imagination. However, John had already received the life-story treatment, and he hadn't left yet. He found John attractive. He was almost positive John found him attractive. And he certainly had been paying more attention to Sherlock than to his string of girlfriends.

"I'll take you up on it if you're offering," he said abruptly.

John stared at him.

"What? I didn't mean—"

"You can't even remember whether your current girlfriend has a dog," interrupted Sherlock. Meanwhile, you watch me when I'm half dressed, and you asked me if I was wearing pants, specifically, in Buckingham Palace. When I made you hit me, you did so, as Miss Adler pointed out, in the way that would be least effective but also least harmful to my looks, and you said something about my cheekbones the other day. Furthermore, you're breathing through your mouth, your pupils are dilated, and you've just crossed your legs."

"Oh, f—I thought you weren't interested in a relationship?"

"Since when are a relationship and sex synonymous?" A terrible thought crossed his mind. What if John really wanted a loving, nuclear family type relationship, and had determined not to act upon, or was even unaware of, his attraction to Sherlock?

"Look, if you don't want to, just forget it."

For a second, John was silent. Then, he stood up, crossed to Sherlock, and kissed him soundly on the mouth.

Sex with John was nothing like wanking or sex with the drunk man. Sex with John was exhilarating, incredible ecstasy. Sex with John brought forth emotions Sherlock didn't even know he could feel, and when he came, he did so with a cry that sounded like a sob, and tears broke free and flowed down his cheeks.

"Sherlock," whispered John, but Sherlock just pulled him down and kissed him again, hard, and then sweetly, trying to express things he didn't even dare think.

And when he woke up so tangled with John, feeling absolutely safe and peaceful, he confronted an idea that was as terrible and frightening as he had feared, but also more wonderful than he had imagined.

"John," he whispered to the still sleeping man, "I think I love you."