an alcoholic drink that both males and females (straight or homosexual) buy for their friends on special occasions, such as birthdays, or just for fun.
The drink is in a tall martini glass or just a glass with a wide opening at the top, and they put a shot glass full of hard alcohol of usually something the receiver will not like (but if they are nice something they will like)at the bottom of the glass and then cover the shot with whip cream. The receiver has to dig through the whip cream and take the shot without using their hands.
"Get Britney a muff dive! It's her 21st birthday!"