You can find this exercise on page 236 of the book Synergistic Golf.
Exercise Type: HEAVY BALL
Exercise Category: HIPS, LEGS - FEET, POWER PRODUCTION, STRENGTH
Stand with feet together and ball in bent arms in front of chest. Lunge right foot forward dipping left knee towards floor. Outstretch arms forward as you step forward. While pausing at bottom, rotate arms, ball, and torso together to the right. Return ball back to front and push off front foot back to start position. Ball then comes back into chest. Alternate lunging legs 20x focusing on correct form.