Next to Padmasana comes Siddhasana in importance. Some eulogise this Asana as even superior to Padmasana for the purpose of Dhyana (contemplation). If you get mastery over this Asana, you will acquire many Siddhis (powers). Further it was practised by many Siddhas (perfect Yogins) of yore. Hence the name Siddhasana.
Even fat persons with big thighs can practise this Asana easily. In fact, this is better to some persons than Padmasana. Young Brahmacharins who attempt to get established in celibacy should practise this Asana. This is not suitable for ladies.
Place one heel at the anus (Guda), the terminal opening of the alimentary canal or digestive tube. Keep the other heel at the root of the generative organ. The feet or legs should be so nicely arranged that the ankle-joints should touch each other. Hands can be placed as shown in Padmasana.
I. Guptasana (Hidden Pose):
The left heel is placed over the organ of generation. The right heel is also over the externel organ of generation. The two ankles are in close apposition or contact. The right toes are thrust inside the hollow between the left thigh and left calf muscles. The left toes are covered by the right leg. Gupta means hidden. As this Asana hides well the organ of generation it is called Guptasana.
II. Vajrasana (Adamantine Pose):
The left heel is placed below the organ of generation. The right heel is placed over the organ. Vajra means adamantine. There is also another variety of Vajrasana. Instructions are given elsewhere.
Sit on ordinary Siddhasana and do Yoni Mudra. It is called Baddhayonyasana. The description of Yoni Mudra is given along with other Mudras.
By sitting on Siddhasana if you raise your hands together up to your chest level, it is called Kshemasana. It is meant that you are praying for the Kshema (welfare) of the public. The palms must be facing each other.