Sit with the legs extended forward. Spread the legs. Bend the left leg so the left heel comes to the groin. Lift the left foot onto the upper right thigh. Bend the right leg so that the right foot goes over the left thigh as close to the abdomen as possible. Straighten the spine. Lift the chest and press the lower spine slightly forward. This position will feel "locked in place." Once you are in it you can meditate very deeply and the position will maintain itself. There are very few exercises or meditations which require this posture, but it is recognized as one of the best asanas for deep meditation.