I don't even have an excuse for this cracky bit of drabble, you guys. I had this theory and then I had a fic and I don't know what happened.

John frowned at Sherlock's retreating back. "Sorry, mate," he said aloud to Lestrade beside him. "Don't know why he always gets like that when I call you by your first name. Does he really not know your name is Greg?"

Lestrade hmmmed.

"I mean, for someone so bloody brilliant . . . aren't you insulted?"

"After all these years, I've gotten used to it." He shrugged. "Find it kind of hilarious, actually. I love how it makes him go a little green."

John tore his eyes from Sherlock (he'd put a tenner on the berk hailing a taxi and leaving him high and dry at the crime scene again) and glanced over at the DI. "There's a story behind this, isn't there? Do I even want to know?"

Lestrade eyed him critically for a minute. "Okay," he said finally, "but you've got to promise me that not a word of this gets out. To anyone."

"Can't promise Sherlock won't deduce it off me and pretend he read my bloody mind, but I'll try."

"Oh, he wouldn't dare." Lestrade snorted. "Right, so the real story - back five or six years ago, when Sherlock was just recently clean and staring to help more often with cases, his brother and I dated for a while."

John blinked. "You and . . . Mycroft? Seriously?"

Lestrade rolled his eyes. "Oi, don't sound so shocked. You knew I was bi."

"Yeah, but you and Mycroft. That's just . . ." John shuddered.

"You're only saying that because you've never gotten to peel him out of one of those suits," Lestrade countered with a smirk. "Anyway, Sherlock then was just as bad with boundaries as he is now. He broke into Mycroft's house and walked in on us while we were . . . well, I'm sure you can guess."

"Oh god."

"A particularly intimate moment, I'll just say." Lestrade bit his lip, obviously thinking back on something amazingly memorable, going by the wistful look on his face. "Sherlock shrieked like a little girl and tore on out of Mycroft's house like we were going to be hot on his heels. He texted me a few minutes later to say he was deleting the entire incident and also might also be gouging out his eyes in the near future."

"He didn't manage to delete the memory, I take it."

Lestrade grinned. "You know that near-eidetic memory of his? Every time he hears the name 'Greg,' he hears it in Mycroft's voice."

"Shit - I call you Greg all the time!"

Lestrade's grin got even wide. "Yes - yes, you do. And it's fantastic."