Sit on the floor with your buttocks supported on a folded blanket and your legs straight in front of you. Press actively through your heels. Rock slightly onto your left buttock, and pull your right sitting bone away from the heel with your right hand. Repeat on the other side. Turn the top thighs in slightly and press them down into the floor. Press through your palms or finger tips on the floor beside your hips and lift the top of the sternum toward the ceiling as the top thighs descend.
Draw the inner groins deep into the pelvis. Inhale, and keeping the front torso long, lean forward from the hip joints, not the waist. Lengthen the tailbone away from the back of your pelvis. If possible take the sides of the feet with your hands, thumbs on the soles, elbows fully extended; if this isn't possible, loop a strap around the foot soles, and hold the strap firmly. Be sure your elbows are straight, not bent.
When you are ready to go further, don't forcefully pull yourself into the forward bend, whether your hands are on the feet or holding the strap. Always lengthen the front torso into the pose, keeping your head raised. If you are holding the feet, bend the elbows out to the sides and lift them away from the floor; if holding the strap, lighten your grip and walk the hands forward, keeping the arms long. The lower belly should touch the thighs first, then the upper belly, then the ribs, and the head last.
With each inhalation, lift and lengthen the front torso just slightly; with each exhalation release a little more fully into the forward bend. In this way the torso oscillates and lengthens almost imperceptibly with the breath. Eventually you may be able to stretch the arms out beyond the feet on the floor.
Stay in the pose anywhere from 1 to 3 minutes. To come up, first lift the torso away from the thighs and straighten the elbows again if they are bent. Then inhale and lift the torso up by pulling the tailbone down and into the pelvis.