Śivasaṃhitā 3.101

This verse opens the description of Siddhāsana, the «seat of the perfected one» or «posture of the adept», regarded by many Haṭha Yoga texts as the most excellent of all āsanas. The instruction begins with the act of pressing (sampīḍya) the perineal region (yoni) with the heel — a gesture that is not merely postural but activates the mūlādhāra cakra and contains the downward-moving apāna vāyu.

Yoni in this technical context does not denote the female organ but the perineum or mūlādhāra region — the «source» or «origin» in a generic anatomical sense. Sampīḍya (from sam- + pīḍ, «to press completely») implies deliberate, sustained compression, not mere contact. Sādhakaḥ, «the one who performs sādhana», signals that this posture belongs to the domain of advanced practice rather than introductory instruction.

Siddhāsana holds a privileged position in the Haṭha hierarchy. The Haṭhapradīpikā (1.37–43) proclaims it the finest of all āsanas and asserts that its mastery alone can yield liberation. Its primary effect is the containment of apāna and the facilitation of khecarīmudrā and mahābandha, making it an āsana oriented fundamentally toward prāṇāyāma and deep meditative absorption rather than physical cultivation.