You can find this exercise on page 183 of the book Synergistic Golf.
Exercise Type: YOGA-STRETCH
Exercise Category: FLEXIBILITY, HIPS, LEGS - FEET
Start in downward facing dog pose, hands down with hips in air, maintaining straight spine and straight legs. Reach right foot off ground and up to the sky keeping leg straight and rotating hips slightly for further stretch. Challenge movement: Kick-lift leg 5 times tapping toe to floor each time and trying to stretch toe farther to sky. Switch legs and repeat.