Vijnana Bhairava Tantra
31: Having filled the murdhanta with the same pranic energy quickly and having crossed it with the help of the bridge-like contraction of the eye-brows, one should free one's mind of all dichotomizing thought-constructs. His consciousness will then rise higher than dvadasanta and then there wiIl appear the sense of omnipresence.
32: The yogi should meditate in his heart on the five voids of the five senses which are like the five voids appearing in the circles of motley feathers of peacocks. Thus will he be absorbed in the Absolute void.
33: In this way, successively, wherever there is mindfulness on whether void, on wall, or on some excellent persons, that mindfulness is absorbed by itself in the supreme and offers the highest benefaction.
34: Fixing one's attention on the interior of the cranium (kapala) and seated with eyes closed, with the stability of the mind, one gradually discerns that which is most eminently discernible.
35: The medial nadi is situated in the middle. It is as slender as the stem of a lotus. If one meditates on the inner vacuity of this nadi, it helps in revealing the Divine.