Under normal circumstances, John might find it comforting that a man can be a genius and still manage to misread a train schedule; under these particular circumstances, he's not particularly inclined toward amusement.
It's nearly two o'clock in the morning. They've missed the last train from wherever-on-God's-green-earth they are in Kent. The only accommodations available are at a sleazy, over-priced Travelodge. The only room available has just one double bed.
Sherlock, for a change, is remarkably sanguine about the whole situation. (Probably because, as John has repeatedly pointed out, it's all his fault! "Come on, John!" he insists, in a suspiciously cheerful voice, "We're grown men. We should be able to share a bed without all this ridiculous fussing!"
John does his best to ignore the giggles of a university student passing by on her way to the ice machine. "What's ridiculous is your inability to read a train schedule! And I still don't see why we had to come out here in the first place…"
"I told you," Sherlock interrupts, "I had to have a look at her bathtub."
"And a picture wouldn't do?"
"John," he scoffs, "please. Anyway, this is it: number 169. Do you have the passkey?"
John hands it over and stands in sullen silence as their room is unveiled. As he'd feared, the room and the bed both are rather smaller than he would like. It was certainly going to be…intimate.
"You sure you're not feeling up to one of your all-nighters?" Of course, it's too much to hope: Sherlock is already sitting on the bed and removing his shoes.
"John, I'm knackered…and so are you!" he adds when he sees John eye the door behind him wistfully. "Honestly, I don't know what you're making such a fuss over! Are you telling me this is the first time you've shared a bed with another man?"
Watson's eyebrows shoot up into his skull. "Are you telling me it isn't yours?"
The look he's treated to is steeped in disdain. "What a dull and conventional life you must lead," Sherlock muses with mock-pity.
Suddenly John is far too weary to continue this conversation. Sherlock had woken him before dawn, insisting they had "important work to do". He's had a day full of filthy bathtubs, pointless chases, dusty back rooms, and circular conversations with paranoid street people. The longer he stands in such close proximity to a warm and inviting (though still disappointingly small) bed, the more conditions he's willing to accept in order to finally get some rest.
With a sigh, he shrugs his jacket off onto a nearby chair.
"Good man," Sherlock responds, standing up and heading for the en suite. He turns back from the doorway. "I presume you'll be wanting the left side of the bed; that's fine. And since you'll be requiring two pillows, you can have mine; I can do without."
John nods and gets on with removing his shoes. It takes a moment before the implications hit him. When Sherlock returns from the loo, John has questions: "Do you watch me sleep?"
"How else would you know which side of the bed I prefer and how many pillows I sleep on?" The minute he asks, he regrets it, as he always does, but it's too late to back out now: Sherlock has adopted his "talking to simpletons" voice.
"John, it couldn't be more obvious! You're a military man. You've seen action, been wounded, feared for your life: it would make sense that you prefer the side of the bed closest to the door so you can monitor any entrance and exit. This is confirmed by the pillow creases I've often observed on the right side of your face: they denote that you typically sleep facing your doorway. As for how many pillows you prefer, your regular visits to the chiropractor are highly suggestive; you might forego his services altogether if you'd learn not to sleep with your head at that ridiculous angle."
Well, it is obvious when he puts it like that…
John starts emptying his pockets, putting his watch, wallet, and car keys on the wardrobe. He turns around in time to see Sherlock folding his trousers and depositing them on a chair; he's wearing nothing but his boxers and vest.
He wants to bluster and blush and protest, but he's tired, so instead he sighs and drops his own trousers; if Sherlock Holmes can be relaxed about sharing a bed with another man, then so can he.