Instructions :

Sit with your legs straight out in front of you, raising your pelvis on a blanket if your hips or groins are tight. Exhale, bend your knees, pull your heels toward your pelvis, then drop your knees out to the sides and press the soles of your feet together.
Bring your heels as close to your pelvis as you comfortably can. With the first and second finger and thumb, grasp the big toe of each foot. Always keep the outer edges of the feet firmly on the floor.

If it isn’t possible to hold the toes, clasp each hand around the same-side ankle or shin.
Sit so that the pubis in front and the tailbone in back are equidistant from the floor. The perineum then will be approximately parallel to the floor and the pelvis in a neutral position. Firm the sacrum and shoulder blades against the back and lengthen the front torso through the top of the sternum.
Never force your knees down. Instead release the heads of the thigh bones toward the floor.

When this action leads, the knees follow.
Stay in this pose anywhere from 1 to 5 minutes. Then inhale, lift your knees away from the floor, and extend the legs back to their original position.