as an update
1) read p-menu 22, the Olympic Squat
2) the stretch with me on the floor can be stretched further in two ways
a. lean over
b. slide your kneeling leg backwards while maintaining an upright posture. Hold on to something on the suspect side to avoid falling over, like a chair or a pole. Eventually this becomes the "pigeon pose" that Dr. G linked to.
I would try both, they seem to hit different muscles or different parts of the muscle.