A sexual act in which partners first engage in anal sex; then, the penis is used to rub or smear remaining fecal matter on the other partner's thigh. Origins of the term come from two sources; (1) the thigh region is referred to in the word "charlie" as in "charley horse" (from the French "char lei" meaning quadriceps) and (2) a pun referring to the consistently meek Charlie Brown character created by Charles Schulz. In metropolitan areas, receiving a "brown charlie" is often used by teens as a sign for exclusivity and love.
Susan proved that she had a boyfriend by having her friends smell the remains of the brown charlie she received the night before.
by Superfriends June 22, 2007