Cranking the Jack
A term derived from "Jacking Off" and the act of lifting a car with a jack. A jack is cranked, which can be tough on the wrists. So can masturbating. So there you go!
"My wrists hurt, I was cranking the jack last night."
"Did you get a blowout?"
"Several" (winks)
"Did you get a blowout?"
"Several" (winks)