How can i get a big butt?

Not sure but: ... working out with a bun exerciser may be the first step. Dancing and Pilates apparently help with that department too. Toning is the key here.

Work it!: Squats, lunges (including backward, side &d curtsy lunges), step ups, hip thrusts, plie, toe taps, Bridge (including marching & single leg bridge), quad hip extension, donkey kicks, single leg deadlift, fire hydrant, split squats, frog pumps, lunge jumps, squat jumps & fire hydrants can all be used to work on butt muscles.