According to Tantra there are three different teachings of the Transformation practices: the special Transformation Yoga; the Teaching of the self-mind (or soul) entering into another's corpse; and the teaching of expelling another's soul from his body so that one's consciousness may enter this body. All these three Transformation practices require, first, the capability of closing the nine gates by words; second, the mastery of Vase Breathing, by means of which all the pranas of different organs are gathered and entered into the Central Channel; third, the mastery of Tumo, whereby the small Ah-word of the red-element in the navel center is able to attract and hold the wisdom Hum word (which is the rider of the subtle prana) at the Heart Center. This is said in the Tantras of Vajra Dakini and of Gdan-bzhi and in their common commentary Bhaba Bhad-ras; and in the Tantra of G'a-sbyor and its commentary, the Fruit-Bearing Pith-Instruction.

I believe that in both cases, whether the self-consciousness enters into the corpse or into another's living body, a special prana performance is required in addition to the requirements and qualifications mentioned before[r_nar:103]. The details may be found in some other sources.

It would be difficult to benefit sentient beings on a great scale with a low-born human body; therefore, it is desirable to have a human body of high class to accomplish the undertaking. Because the possession of a sick, aged, crippled body would handicap self-improvement as well as altruistic deeds, one resorts to the Yoga of Entering Another's Body to procure a fair and healthy body.

According to gurus there are three requirements for practicing this Yoga: first, the person who intends to practice this yoga must have an infinite compassion for all sentient beings; he must be absolutely sure that great benefits and boons for sentient beings will be achieved if he performs this yoga; he also must have mastered both prana and mind. A yogi who meets these requirements and conditions may then proceed to a very secluded, sheltered place. He should dispense with all distracted thoughts, keep away from all wordly activities, prepare the offerings, and establish the altar for the patron Buddha. With all these arrangements made, he should then engage himself in meditation under strict Confinement of Contemplation[r_nar:104].

Then he should prepare a Mandala painted black as the supporting-platform and put a human skull on it. In the center of the human skull a Hum word should be clearly written with a white stone (chalk). Visualizing himself become the Patron-Buddha, he then recites and meditates on the prayer of Seven Wishes of Bodhisattva Samantabhadra. Then the yogi visualizes a Hum word