Bounce

Bounce is a comical quest achievement introduced in Cataclysm. It requires the player to jump onto a trampoline normally used for the quest The Bears Up There and to remain on it through 20 consecutive bounces. The trampoline is located at the Whistling Grove in Mount Hyjal and accompanied by Keeper Taldros.

Strategy
To accomplish this achievement, step onto the trampoline to begin bouncing. While you are bouncing, you do not need to jump. Each time you bounce, turn yourself to face the middle of the trampoline while you are in midair such that you are facing it by the time you land.