WoWDB

Tournament Favor is found in Black Rook Hold.  Technically, it's in the Ravencourt sub-zone of that area, but it's more easy to locate if you consider it part of the Black Rook Hold Arena (a place for FFA PvP).  It's inside a Medium Treasure Chest that's tucked back in an alcove beside the only way out of the arena.  The hall itself is landmarked with a red carpet; none of the other small semi-open rooms adjacent to the arena have a carpet. Edit: The toy was moved from a treasure chest to being a reward of a class Order Hall mission.

The toy causes your character to /flex for 12 seconds, while you hear a cheering and clapping audience in the background.