Esoteric Teachings of the Tibetan Tantra, by C.A. Musés, , at sacred-texts.com
If one intends to attain the Highest Accomplishment (Buddhahood) in one's lifetime, one should practice both the Arising Yoga and the Perfecting Yoga. Each of them has three different practices: the With-Form-Practice, the Without-Form-Practice, and the Extremely-Without-Form Practice. This is said in the Book of Sgron-gsal (The Light of the Lamp). Here, some explanation of the term "Practice" is needed. The so-called "Practice" [with and without form] means the practice of enjoying all pleasures with a spirit absorbed in the realization of the Dharma-essence [the very heart of Tantric practice, whether Hindu, Taoist, or Buddhist.—Ed.]; especially it implies the enjoyment of the negative embodiment. Through this practice on the (excessive) enjoyments, the Enlightenment on the Soleness will be elevated to consummation. The Extremely-Without Form Practice denotes the practice of the Wisdom-Yoga, which is a practice of enjoying the blisses of the negative embodiment *. The other practices imply the Karma Yoga. [Only the Extremely-Without-Form is karma-free.]
These practices can be performed in three different ways: the elaborate way, which is the joyful performance including dancing and singing, etc.; the modest way; and the simplest way. These practices are applied at the beginning
stage of the Illusory Body Yoga practice, and at the time when one wants to attain the Without-Learning-Two-In-One Position from the With-Learning-Two-In-One Position. These are the three times one may carry out the practices. It is for the purpose of planting the Dharma-seed in the mind of sincere disciples that I have mentioned these practices and given all the essential instruction in full. For fear of involving too many words, the foregoing instructions are not given in detail. If one wants them elaborated, one may study and search in the works of the Collective Pith-Instructions (of Gsun-adus).
What happens when the Final Accomplishment comes into being?
Having attained the position of the With-Learning-Two-in-One, one furthers the meditation on the Light Yoga; thus, in time, the dualistic thoughts and manifestations are purified and the absolute Dharmakaya is fully unfolded. The Two-in-One-Illusory Body of the With-Learning is transformed into the Two-in-One-Body of the Without-Learning. As long as the Saṃsara exists, this body will not change or vanish; (for the welfare of sentient beings) this pure body of Buddha will remain.
Here, the two-Hindrances-Free Objective-Light is the immutable Dharmakaya itself. The Subjective-Light is the Wisdom Dharmakaya itself; it is also called the Body of Great Bliss. Coexistent with it is the Body-of-Form, or the Sambhogakaya, which is the (consummated) transformation of the Mind-Prana. These two Bodies are one in essence and two in aspect. This Body-of-Form is identical with the Not-Two-Wisdom-Body [better: "Non-Twofold Wisdom Body" Ed.]; this is frequently mentioned by the gurus. Some people say that the Body-of-Form cannot be
ascribed to (or do not exist in) the realm of Buddha, but only appears through the Karma of sentient beings 'or, more accurately speaking' this Body-of-Form only appears as a reflection from the mind-mirror-of-Karma of sentient beings. They also claim that this Body-of-Form is in essence insensible and non-conscious. Some even say that in the Absolute Accomplishment (or Enlightenment) there is no wisdom whatsoever. One should know that all these sayings are false!
From this Unparalleled Two-in-One Body emanates the supreme Nirmanakaya, and from it are conjured numerous Transformation-Forms.
262:* We feel that 'Body of Non-Form" better expresses the meaning here, which points to the Without-Form Practice of the Anuttara Tantra.—Ed.