Sam knows what he's reaching for, so he turns and grabs the chair, bringing it over. "It'll come out easier if you raise a leg." Because, yes, he's done this before. "I'll let you take care of it because...well, because." They weren't that close. Sam wasn't Castiel's dom, even if the one who had claimed the title was a piece of absolute shit.

Sam turns his back, giving Castiel as much privacy as he can manage. He'll absolutely help if Castiel asks for it, but he won't offer. Not just at this moment.