You can find this exercise on page 292 of the book Synergistic Golf.
Exercise Type: YOGA-STRETCH
Exercise Category: BALANCE, FLEXIBILITY, HIPS, LEGS - FEET, POSTURE, STRENGTH
Start in Warrior I position with right foot forward and left foot back on ball of foot. Turn left foot outward flat and open arms parallel with floor so chest faces left. Palms face down. Hold strong in this position for 10 seconds. Repeat other side.