How to get a round butt?

I have a butt I think it's small and shapeless. I want to have a full round butt. When I ran track my butt was perfect but since then it has lost it's shape. I have been doing the squat and ab challenge. Currently I'm on day 8 I'm not sure if I'm doing it right because I feel my thighs are more firm and thicker not my butt. I naturally have thick thighs I have legs like a track star just no butt. I do squats, lunges, leg lifts, back kicks, I do it all but I feel like my thighs are being worked more than my butt. Help me.