1) You are within the game World of Warcraft, and are either storming an Alliance city or or of Warcraft's many Battlegrounds.
2) When you soundly run into a fist-fight you are sure to win (or lose, but want to go out in style)
3) When awestruck at something totally Amazing to all, or looking at a Hot girl
Guy 2: Shit, that guy wants a fight!
*Guy 2 charges*
Guy 2: For the Horde!!
Usually shouted when a particularly orkish looking, but not nescisarily overweight, girl comes into vision
Jazz: For The Horde!