Naṭarāja's stance
It is worth remarking further that Śiva tramples Apasmāra with His right foot. The right foot, it may also be noted, is also easily the Puruṣa portion of His own body. The right half of every individual is the puruṣa-bhāga, and the left, the prakṛti-bhāga. Thus the Puruṣa portion of the Śiva's person imparts the Puruṣa nature to the crouching figure - a very natural development - of going beyond the realm of Nature! The left portion of the body being feminine, there is a natural "shyness" on its part, and hence the genitalia (howsoever it be in truth - for it should indeed be a mystery extraordinary) has been "covered" by the lifted left foot. (Modern ugly perversions apart, the feminine is naturally the more bashful). This particular "still" posture of Naṭarāja thus also achieves this "covering up" of the "enigmatic" portion of the body in a very graceful and natural manner issuing as a matter of course in the course of the performance.