You mean on ground or in saddle? On ground I just move the butt in circle away from me that's it. Frankly I don't believe in repeating the same exercise over and over on ground - it's boring for me and obviously boring for my horse. So I just practice it once in while or when my horse misbehaves. In saddle I do lots of transitions and backing so she'd work from her hind. I also do turning her butt from my leg (with front legs frozen in place).