John notices the bullet wound, and gently runs his fingers over it. He wants to ask Sherlock where it's from, but at the same time, he's too busy listening to the other breathe. Another time, then. He'll ask. He'll ask where the marks came from, where his scars are from. He hasn't noticed the ones on Sherlock's back, though. He hasn't gotten that far.
As he moves down Sherlock's stomach, he stops at the top of his pants, glancing up at him. He's stopped now, his hands resting on the other's bony hips as he stares. In a weird way, he wants to hear Sherlock tell him he wants this to continue.