You can find this exercise on page 92 of the book Synergistic Golf.
Exercise Type: PILATES
Exercise Category: BACK, POSTURE, SHOULDERS
Lie face down with hands by shoulders and legs squeezing together. Inhale prepare. Exhale reach arms forward and top of head away from body parallel with floor. Inhale and circle arms back toward hips, lengthening and extending upper spine. Repeat 10x. Focus on keeping tension away from upper back and neck. Support spine with abdominals throughout movement.