a meditative seating posture in which the left heel presses the perineum (stimulating the mooladhara chakra); also called as the adept's pose or the 'pose of perfection'.

(Sanskrit, "the perfect pose") A seated posture for meditation or Alchemy. It is described by Swami Sivananda as follows: "Next to Padmasana comes Siddhasana in importance. Some eulogise this Asana as even superior to Padmasana for purposes of Dhyana. If you get mastery over this Asana, you will acquire many Siddhis. Further it was b [..]