This is a question i would love to know and most women. Really the only thing you can do to increase the size of your butt is exercise of course. But you should try to cut out the junk foods and fattie foods and i know that helps too. Running, hamsting curls, lunges, squeezing your butt, climbing the stairs, and kick backs are some exercises you can do to tone your butt and leg muscles. Lastly there are the squats which to me are the best and my favorite. You should do these exercises daily and should see an improvement.