The Cow Dance is a minigame of sorts in Bully.
The Cow Dance can only be attempted when Jimmy is wearing the mascot costume.
Jimmy can attempt a cow dance at any time. If there are students nearby, they'll stop to watch and both cheer him on and laugh at him. During The Big Game students will demand he dance for them, and if he refuses or fails to perform one correctly, they'll attack him but if he does it correctly they leave him alone.
The controls involve pressing one of four buttons as specified by the game. If the player hits the correct buttons, Jimmy does the correct dance move, if the player hits the wrong one, Jimmy ends up off balance. If he makes three mistakes, he fails the dance. After successfully completing a dance, he does an elaborate bow.
The game keeps track of both attempted Cow Dances and successful Cow Dances. There is no further reward for completing one, however.