You can find this exercise on page 220 of the book Synergistic Golf.
Exercise Type: PILATES
Exercise Category: ABDOMINALS, BALANCE, POSTURE, STRENGTH
Lie on back with spine imprinted into floor and legs straight to ceiling pointed and arms long overhead. Inhale slide shoulder blades down back and reach arms toward ceiling then sequentially roll spine off mat one vertebrae at a time to balance just behind sit bones. Arms stay by ears. As you exhale, maintain torso in place while lowering straight legs down to floor. Inhale return legs to V position. Exhale and roll spine down to mat through imprint and arms stay by ears. Repeat 5x.