Sherlock means well when he asks these things, really he does. John knows that, has learned it well enough over the past several months. That doesn't excuse the request.

"Sherlock, I am just not going to tell you, all right?"

He looks perturbed, as if John refusing to answer the question is both illogical and mildly offensive. "It's not a personal question, John, I don't-"

"Not a...Not a personal question, Sherlock? You asked me about my teenage sex life, all right, that's personal." The first week, they'd worked out a rule about personal questions, a rule that Sherlock had never seemed to have a problem bending or ignoring altogether.

"I have no problem telling people about our sex life, John, so sex questions are not personal."

John gapes. "Who do you talk to about our sex life?" Waves his hand in Sherlock's direction. "No, wait, don't answer that, I don't want to know yet another reason Lestrade looks at us like I've grown an extra limb or three."

"Not Lestrade, John." A sneer. "Answer the question, I need it for a case."

Exasperation. You'd think they'd have come up with a vaccine for it by now with Sherlock bloody Holmes being alive and breathing and asking things. "What case could possibly rely on you knowing my teenage sex stories?"

"Stories?" Sherlock emphasizes the 's' just a touch, not so much anyone would notice if they weren't used to parsing genius-speak.

"Stories, yes, Sherlock, I was a sexually active teenager, all right, but you don't get to dodge this. What case?"

A huff. "Our murdered teenage boy. He wasn't sexually active according to his parents."

"Well, no, Sherlock, teenagers don't tell their parents when they're-"

"I know that, thank you, John. But his friends say the same thing."

"So?" John plops into his chair - the wet and cold are getting to his shoulder, and he'd kill a cabbie for a drink. "He wasn't having sex, so what?"

"But he had condoms, John."

"So? I had condoms in my room for a year before I had sex."

"An opened box?" Sherlock's face pulls into its skeptical look.

John bashes his head against the chair a few times. "Shit, fine, all right. Sometimes, teenage boys use condoms when...they are alone. Sherlock, all right? For the mess."

Sherlock looks puzzled.

"The mess, Sherlock. When they're alone." John makes a half-hearted gesture with his fist.

Sherlock's face clears. "Ah, perfect! See, John, all you have to do is tell me things when I ask and we'll avoid all this trouble."

"You-" he shakes his head. "No, Sherlock, all youhave to do is tell me what you need to know, specifically. If you want to know why a teenage boy who is by all reports not having sex would have an opened box of condoms, ask me that. I can answer that."

"And if I want to know who the first man to fuck you was?" A nearly-hidden leer.

"Ask me that." John grins in return.

Sherlock moves quickly and silently, in that way he's finally perfected. "Do tell," he says, his eyes inches from John's.

"John Forester, from sixth form." John bares his teeth in a grin, loves to make Sherlock jealous, loves to play.

"Did it feel like masturbation, to fuck a man with your name?" A fierce smile.

"Not what you asked."

The air between them is fairly crackling. "Ah, yes, stupid of me. He fucked you, then. Who was the first man you fucked?"

"John Forester, from sixth form." A wicked smile, mirrored on Sherlock's face. "And yes, it was a bit masturbatory, but he was bloody gorgeous, I got over it."

"Better than me?"

"Never."

"Ah, that's all right then." Sherlock stands, pulling John up with him. "Bed?"

"Bed."