Vijnana Bhairava Tantra
81: If one maintains the mouth widely open, keeping the inverted tongue at the center and fixing the mind in the middle of the open mouth, and says vowelless ha mentally, he will be dissolved in peace.
82: Seated on a seat or bed, one should contemplate one's body as without support. By this contemplation when all props of one's thought vanish i.e. when one's mind becomes free of thought-constructs, then in an instant, all his old mental dispositions (lying in the unconscious) will also vanish.
83: O Goddess, owing to the swinging of the body of a person seated on a moving vehicle or owing to self-caused swinging of his body slowly, his mental state becomes calmed. Then he attains divyaugha and enjoys the bliss of supernal consciousness.
84: O Devi, having fixed the gaze continuously on the clear sky (without blinking) and with a steady awareness, at once the nature of Bhairava is achieved.
85: The yogi should contemplate the entire open space or sky under the form of the essence of Bhairava and as dissolved in his head. Then the entire universe will be absorbed in the light of Bhairava.