I'm on my third belly dance lesson, and I'm a total newbie to any kind of dancing. I'm working on hip isolations, and experiencing pain in my knees. It's not excruciating, but I don't want to hurt myself. I asked my teacher, and she wasn't much help. She just said to be sure and keep my knees bent, which I'm already careful to do. How can I protect my knees while moving my hips? Thanks!