I would like to start working with a paint yearling that I have and would like to teach it to stand still while I'm shooting off of her. What is the best method? I have heard that cracking a bullwhip near a horse was a good method... I plan on starting with my Henry Golden Boy and .22 Shorts and then work up to the 12 gauge. Any advice?

P.S. She is VERY gentle and has had the saddle put on her a couple if times, but is too young to be rode.