Vijnana Bhairava Tantra
26: When the middle state develops by means of the dissolution of all dichotomising thought-constructs, the prana-sakti in the form of exhalation (prana ) does not go out from the centre of the body to dvadasanta nor does that sakti in the form of inhalation (apana) enter into the centre from dvadasanta. In this way by means of Bhairavi who expresses herself in the form of the cessation of prana (exhalation) and apana (inhalation), there supervenes the state of Bhairava.
27: When the Sakti in the form of exhalation (recita) is retained outside, and in the form of inhalation (purita) is retained inside, then at the end of this practice (Kumbha), the Sakti is known as Santa or tranquilized and through that Sakti Santa Bhairava is revealed.
28: Meditate on the Sakti arising from the muladhara cakra, scintillating like rays (of the sun), and getting subtler and subtler till at last she dissolves in dvadasanta. Thus does Bhairava become manifest.
29: Meditate on that very lightning-like sakti (i.e. Kundalini) moving upwards successively from one centre of energy (cakra) to another upto three fists i.e. dvadasanta. At the end, one can experience the magnificent rise of Bhairava.
30: Twelve successively higher centres of energy associated with twelve successive letters should be properly meditated on. Each of them should at first be meditated on in a gross phase, then leaving that in a subtle phase and then leaving that also in the supreme phase till finally the meditator becomes identified with Siva.