"I--" Dean says, because How to get it off is not the best thing to say to a girl of twelve. "Uh," he says instead.
"Like is it more comfortable?" Claire asks. "Or do I need to get a sports bra?"

Later, Dean tells Sam about it. Sam is not sympathetic. "You know you're going to have to explain her period too," he says.
Dean makes this face: DDDDDDDD: