The Accomplished Pose
Yonisthanakamankaghrimoolaghatitam kritva dridham vinyase-
Tmendhe paadamathaikameva hridaye kritva hanum susthiram||
Sthanuha siyamihendriyochaladrisha pashyed bhruvorantaram
Hyetanmokshakapaatbhedajnakam sidhasanam prachyate ||35||
Hatha Yoga Pradipika- 1:35
Meaning: Press the perineum with the heel of one foot, place the other foot on top of the genitals. Having done this, rest the chin on to the chest. Remaining still and steady, with the senses controlled, gaze steadily into the eyebrow centre; it breaks open the door to liberation. This is called siddhasana.