You can find this exercise on page 169 of the book Synergistic Golf.
Exercise Type: BIG BALL
Exercise Category: ABDOMINALS, ARMS - HANDS, BACK, CHEST, FLEXIBILITY
Similar to rib tilts, sitting tall on top of big ball with hands on hips to help prevent any movement of lower body. Rotate ribcage in clockwise motion 10x, then repeat counterclockwise 10x. Practice increasing size of circle of rib rotation. Sit tall and maintain long spine to avoid compressing and shearing.