Nearly a year of living with Sherlock had honed John's reflexes to a near-superhuman level. It was therefore not at all surprising that John caught the deck of cards Sherlock lobbed at his head before he'd even really consciously realized he'd just awoken from a nap on the sofa.

"John, I need you to teach me how to play poker."

John levered himself up to sitting and scratched his chest with a yawn. "You assume I play," he mumbled, blinking against the slanted afternoon light coming in the window. "What brought this on? Case?"

Sherlock plonked down in his armchair, pouting at the ceiling with limbs all awry, and sighed dramatically. "I deleted it, apparently."

"You . . . right." John tossed the deck onto the coffee table and scrubbed the heels of his palms over his eyes. "You deleted poker, or you deleted the reason you want to learn it?"

"Deleted all card games." Sherlock rolled his head along the back of the chair to look at John, as if actually holding it up like a normal person was too much effort. "Poker in particular. It's been brought to my attention that I may be missing valuable data." He huffed. "You must know how poker is played - you're a gambling addict."

Bloody . . . John crossed his arms. "I had a gambling problem at one time, yes. But I haven't wagered for years. And it wasn't poker. Last time I played poker, I think it was strip poker back in uni."

"So teach me that."

John blinked. "Sherlock, do you even know what strip poker is?"

Sherlock smiled. It was his I'm-going-to-get-my-way-so-why-are-you-arguing smile. The most annoying one. "No, which is why you need to teach me."

"It involves getting naked. Together."

Sherlock shrugged, an impressive feat considering his current boneless-sprawl state. "I'm not shy."

"Figured that out, ta." It's not that Sherlock wandered around starkers all the time, but John got an eyeful of blindingly pale pectorals whenever Sherlock decided he couldn't be bothered to put a shirt on under his robe. Which was on a pretty regular basis. Sherlock had a threadbare grey t-shirt on now, thankfully, but even the clash of the grey shirt, the olive-and-tan-striped pajama trousers, and the navy blue robe wasn't enough to counteract his natural grace. And confidence. "Maybe I am," John added.

"You're not."

There wasn't really any point in arguing - Sherlock would poke holes in the lie immediately - so John let it go. "It wouldn't be a fair contest," he said instead.

Sherlock rolled his eyes. "I assure you, John, I'll pick up the rules quickly-"

"Not that." God, how could the man be so dense? "It's a game about reading people, you berk. I'm going to end up in my underpants before you've even taken off one sock."

Sherlock blinked, then sat up straight. "Explain."

"Poker is . . ." John thought for a moment about how to say it. "Well, there are different versions, but all of them boil down to math and bluffing. You get your hand, you have a higher or lower chance of it being the best hand at the table, and then you bet against everyone else and the winner keeps the pot. You win at poker by convincing your opponents you have better cards, not by luck. And since you're better than I am at lying, reading body language, and calculating probabilities on the fly, I'd lose."

"No." Sherlock shook his head. "Explain the part about your underpants."

God, this whole conversation was a terrible idea. Too late to cut and run, though. "The point of strip poker," John said in as disaffected a voice as possible, "is to make the other person have to strip. Instead of wagering for money, you wager for items of clothing. The more you lose, the more you have to take off. Generally the game ends with everyone drunk, some sort of sexual activity, or both. It's not the kind of thing I'd invite Mrs. Hudson up for."

"Oh, she knows how to play," Sherlock said with a graceful wave of his wrist. "She's the one who mentioned poker with her late husband and his friends. Alerted me to the fact I was missing potentially valuable knowledge. She didn't call it strip poker, but it was heavily implied."

"Jesus." That was going to take some rather strong brain bleach to get out. John frantically tried to think of another excuse. "You're barely dressed." It was the only one he could come up with.

Sherlock glanced down at his pajamas, then shrugged. "Call it a handicap."

Christ. "I don't want you squirreling an image of me naked away in your mind palace somewhere."

"So I'll play blindfolded." Sherlock leaned forward, planting his elbows on his knees, and grinned. "Would that be more fair? Me with four pieces of clothing to your eight, blindfolded so I can't see you and can't read your non-verbal cues, and a novice at the game? I'll even promise to publicly acknowledge that you beat me at poker, if you want to brag to Lestrade afterward. If you win, of course."

"Of course." John sighed, but his mind was already racing ahead. This wasn't the worst way Sherlock had ever proposed to spend a lazy afternoon, by far. It was non-destructive, didn't involve rotting body parts in the crisper, and might actually allow him the chance to ogle Sherlock's chest without feeling like Sherlock was going to catch him out and deduce him. John wasn't as sure of his absolute straightness as he had been when he moved in to 221B, but that didn't mean he wanted Sherlock noticing and analyzing anything.

"If you promise to never ever ever mention it was strip poker," he finally said, "and you promise not to cheat, then we can try it."

"Excellent." Sherlock practically leapt out of his seat, grabbed his blue scarf off the hook near the door, and presented it to John. "I trust this would be an adequate blindfold?"

John held it up over his own eyes and squinted through it. The fabric was surprisingly thin for being so warm and sturdy. If he focused, he could make out a Sherlock-shaped object in front of him, but there's no way Sherlock would be able to read the cards. Or John's face. "You look at your hand first," he declared. "Before I see mine. Then no peeking after that."

The Sherlock-shaped blob inclined his head. "I have an excellent memory. That's acceptable."

"Right. Drag your chair over here, then." John sucked in a deep breath and let it out in one long exhale. I'm seriously screwed.