You can find this exercise on page 152 of the book Synergistic Golf.
Exercise Type: YOGA-STRETCH
Exercise Category: FLEXIBILITY, LEGS - FEET, LOW BACK
Sit tall with legs extended straight and wide apart. Goal is to maximize and widen the V position. Place hands on floor between legs to start. Inhale to prepare. Exhale hinging from hips forward leading with chest to floor. Pause. Return to start position and repeat 5x slowly. Do not bounce in this position! Hold abdominals tight throughout exercise.