HOW: While laying on your side, bend your knees and bring them forward. Rotate the top knee up as far as you can and hold that position. Then, rotate your ankle up towards the ceiling as your knee stays still, lower your foot down and repeat.
FEEL: You should feel all the deep muscles in your hip and glutes working.
COMPENSATION: Don’t roll forward or backward while rotating your hip, keep your knee still as you lift your foot up/down off the ground.