A girl within a certain group of people (such as a high school class) who is known for administering blow jobs and/or other sexual favors. The term is a play on words, leading one to believe it is referring to the academic superior of a class.
Guy 1: "Man, Katie is such a bitch!"
Guy 2: "Yeah, she's the head of the class."
Buy a
Head of the Class
mug!
