Person 1: "Stop inviting me over to your house."
Person 2: "You're really mean to me, even though I'm your best friend. You may wanna get checked for Waznism."
The predilection for masturbating into a full hot water bottle. At the crucial moment of ejaculation, an involuntary spasm overcomes our protagonist, leading to a back-ejaculation (or ebaculation, if you will) of the hot-water bottle's contents onto that most sensitive of areas.
"Don't worry," the orthopaedic surgeon said to Peter's mother, kindly. "There's nothing wrong with his legs. It's just a particularlyvigorous case of adolescent John Waynism."