Penstruation: menstruation that is brought on by penile penetration, despite the subject being pre or post menstruation. Penstruation is often discovered, post-coitus, due to bloody sheets (or other stained lovemaking surfaces). Anecdotally: women who have experienced penstruation report that it is associated with passionate, vigorous (condomless) sex, a fairly well endowed partner, and voluminous deposits of
sperm, which may be why neither
party usually minds the
bloody after-effects too much.
"So, in a case of penstruation, who is responsible for washing the sheets, the girl or the
guy?"
"
Oh, the
guy, of course."