You can find this exercise on page 171 of the book Synergistic Golf.
Exercise Type: PRE-ROUND WARMUP
Exercise Category: CHEST, FLEXIBILITY, LOW BACK
Stand facing away from a wall with feet hip distance apart and about 12 inches from the wall. Rotate clockwise and place hands parallel with floor on wall behind you. Rotate the other way and do the same. Focus on lifting spine upward. Repeat 20x. Then practice rotating without lifting up bottoms of feet off floor.