When a man bitches and moans in a truly over-dramatic fashion, similar to the effects PMS has on a woman's mood. Can be used as a noun, verb or adjective (
manstruate, manstruator,
manstruating, etc.) Could also mean for a man to be "stroking his ego" through anger, similar to
masturbation or angry sex but without the dick involved.
"Edward is throwing a tantrum at Betty for
overcooking his steak. Edward has been
caught in the act of manstruation."
"You're one hell of a manstruator when you haven't had your beer"
"Better be careful! If my father catches us in the act of
sexual intercourse, he'll manstruate at you for sure!"