In the ancient days of the 1970s, when dinosaurs ruled the earth and men were tiny squeaking rodents (not all that much has changed), a cinderella fuck was getting intercourse from a girl in her dorm room before the curfew when men were thrown out of the women's dorms. If you were really lucky, she'd want to get started early, but a lot of women preferred to start the cinderella fuck at about ten minutes to midnight. The opposite of a "rule of half past four."

When you fuck a girl, then steal one of her shoes.