"Can I see it?"
It wasn't the first time Sherlock had asked a random question, seemingly out of the blue, but this time John knew instinctually what he wanted.
"Yeah. Sure."
He closed the door—hoping that Mrs. Hudson wouldn't barge in and discover more fuel for her rumors—and then quickly shucked his jumper. Immediately Sherlock was at his side, fingers dancing over his scar.
"No exit wound," he murmured, touching a ridge. "They had to dig it out. You were kneeling—" Sherlock's mouth suddenly snapped shut. Again John knew what he wasn't asking.
"It wasn't my dad," he said dryly and before he'd met Sherlock's ordinary, obviously doting father John wouldn't have dared to make such a joke. "They were buddies. Three comrades I'd had for the whole run. We were close in a battlefield sort of way, you know? And all of us were accumulating scars. Smaller ones." John pulled up his jeans to show the scratches on his calf. "If we had to come out battered we wanted a say in how it was done. It was about… control. Having control. Even if only a little."
Sherlock nodded and silently moved away. Before he left entirely though his hand shot out again, bestowing a caress on John's side. There, carefully placed, were three distinct cigarette burns.