"John?"
"Mmmmm...yes, Sherlock?"
"I have something to tell you that might upset you."
"Oh no. What's wrong, then?"
"You're not real."
"What? Are you bonkers? Of course I'm real!"
"No, no you're not. Just listen. You are a character that was created by Sir Arthur Conan Doyle and re-hashed for the 21st century by Steven Moffat and Mark Gatiss. So am I. Neither of us are real people. You're played by an actor."
"No...no way. I don't think those people would write about us having mad hot gay sex."
"They didn't. That was some horny queer twenty-three-year-old Minneapolitan with clinical agoraphobia and a laptop. Listen, you are actually an actor named Martin Freeman who fuck everyone won a BAFTA. And I am an impossibly sexy ginger man with cheekbones that can cut glass named Benedict Cumberbatch."
"Oh, so that's why the carpet didn't match the drapes. You're a GINGER."
"Yes, of course."
"Well then. This is a disturbing revelation."
"That I'm a ginger?"
"No you git, that I'm a fictional character from the 1800s."
"Oh, yes. Now that we know we're actors, we need to tell the world that we know about the porny fan fiction that exists featuring us."
"You mean the stuff that we were just in? Those stories by that, what did you call them, uh, queer Minneapolitan agoraphobe?"
"Yes. That's it. Cavan, we know about the porn."