You can find this exercise on page 279 of the book Synergistic Golf.
Exercise Type: PRE-ROUND WARMUP
Exercise Category: HIPS, LEGS - FEET, STRENGTH
Stand tall with feet slightly wider than hips and toes aiming outward at 45-degree angles. Inhale lowering buttocks and hips down and back as if to sit. Knees should stay still and weight remains mostly in heels. Feel stretch in inner thighs and tops of thighs. Pause slightly at bottom. Exhale squeezing buttocks and push through heels to stand up. Repeat 10-15x with focus on strong hips without pressure in knees.