You can find this exercise on page 123 of the book Synergistic Golf.
Exercise Type: PILATES
Exercise Category: ABDOMINALS, BALANCE, FLEXIBILITY, STRENGTH
Sit and put the bottoms of both feet together. Place hands under and on outside of feet while leaning back and balancing. Flex your spine, bringing your chin toward your chest. Using your abdominals to assist in balancing behind your sit bones, inhale and roll backwards. Exhale and return to the starting position. Repeat 10 times.