John pushes the door open to reveal a small, tidy room. There's an armoire big enough for the two of them to share, a small telly for Sherlock to yell at in the evening, and there, in the centre of the room, two single beds stacked one on top of the other, connected with a short rope ladder. He sighs and steps to the side just in time to let Sherlock bluster into the room.
"What on earth is that, John?" he gestures to the sleeping arrangements.
"They're bunk beds, Sherlock. This room is typically used by younger guests, but it was either this or a room with one large bed."
Sherlock just glares at John and shakes his head, as if to say Well why didn't you take that one?
"Because I am not sharing a bed with you unless I absolutely have to, Sherlock. Besides, it's not like you're actually going to sleep, so what do you care what the bed looks like? Think of it as an experiment."
At this, Sherlock's face lights up as he climbs the ladder to the top bed, reminding John oddly of some sort of tall, gangly primate. Grinning, he peers down over the edge of the bed, hair flopping about absurdly.
John just groans tiredly and lowers himself onto the bottom bunk.