In Tibetan Yoga and Secret Doctrines (Evans-Wentz, trans., London: Oxford University Press, 1935) dream yoga is one of six subtypes of yoga elaborated by the Tibetan guru Marpa and passed down by his well-known disciple Milarepa. The practice has a number of steps, which permit the individual to gradually gain increasing amounts of control in the dream state.
First, the individual must become lucid or wake up in the dream state.
Second, the dreamer must overcome all fear of the contents of the dream so there is the realization that nothing in the dream can cause harm. For instance, the lucid dreamer should put out fire with his hands and realize fire cannot burn him in the dream.
Next the dreamer should contemplate how all phenomena both in the dream and in waking life are similar because they change, and that life is illusory in both states because of this constant change. Both the objects in the dream and objects in the world in the Buddhist’s worldview are therefore empty and have no substantial nature. This is the stage of contemplating the dream as maya, and equating this sense of maya with everyday experience in the external world.
Fourth, the dreamer should realize he has control of the dream by changing big objects into small ones, heavy objects into light ones, and many objects into one object. He should also experiment with changing things into their opposites (i.e. fire into water).
After gaining control over objects and their transformations, the dreamer should realize that the dreamer’s dream body is as insubstantial as the other objects in the dream. The dreamer should realize that he or she is not the dream body. While this realization is very difficult in normal waking existence, presumably it is quite obtainable in the dream since the dreamer who has control over dream objects could, for instance, alter the body’s shape or make the dream body disappear all together.
Finally, the images of deities (Buddhas, Bodhisattvas, or Dakinis) should be visualized in the lucid dream state. These figures are frequently seen in Tibetan religious art (thangkas) and used in meditation. They are said to be linked to or resonate with the clear light of formless “suchness.” They can therefore serve as doorways to Sunyata or clear light. The dreamer is instructed to concentrate on these images without distraction or thinking about other things so that the qualities of each of these personifications of the enlightened divine are internalized: You awaken through becoming one with them while lucid dreaming.