An instance of sex where a male cums inside of a cup, and then the female drinks the contents of the cup.
Let's commit a cup incident tonight!
A type of sexual intimacy where a female grabs a cup, and tells the male to fill the cup with his cum. The male accepts, and fills the cup with his cum, which then the female drinks the contents of the cup.
Female- heyyy, want to commit a cup incident?
Male- yeah, sure :)