Chirrut can hear the rasp of those hands against wood, and has to fight very hard to not imagine those hands

(so warm, so gentle, so strong)

in other places, doing... other things.

He hopes desperately that his flush is hidden in the heat of exertion.

"Nothing's going on, mother hen. If you don't want to spar, I'm going to get clean. I stink."

AKA he's going to hide in the sonic until the maddening noise of it drives all other thoughts out of his head.