Lalana Rasana are the left and right nadis or channels in the human body. The Buddhist tantric tradition accepts an inner physiology of nadis (channels), vayus (winds), bindus (drops) and chakra (wheels). The channels are the pathways of the various types of consciousness, and it is said that there are as many as 72,000 nadis in the body. Nevertheless, three main channels are recognized avadhuti (the central one), rasana (the right) and lalana (the left).
The central channel is also called Rahu, the asura who periodically swallows the moon. It is associated with mind in a three-fold scheme of mind, speech and body (citta, vak, kaya). It goes right through the middle of the various chakras.
The two side channels are placed next to it, without any intervening space. The right channel, rasana, is associated with the sun and with vak (speech) and is red in color. It corresponds to the conceptual construction of a subject, a grahaka (perceiver).
The left channel, lalana, is associated with the moon and the kaya (body). It is generally described as being white. It corresponds to the conceptual construction of an object, something to be grahya (perceived). Descriptions of the colors and characteristics of the channels may vary at times. These three nadis resemble sushumna, ida and pingala.
Anuttarayoga Tantra (highest Yoga Tantra) is considered to be the ultimate level of Buddhist Tantra. It is divided into two progressive stages of practice – the utpanna krama (generation stage) and the nishpannakrama (completion stage).
Once the practitioner has mastered the generation stage, he or she will meditate on the channels, winds, drops and wheels. This is the basis for the practice of the completion stage. Vijnana (consciousness) is carried by the winds, and its characteristics depend on the channels it moves through. In other words, our conceptualizations are a result of the unchecked flow of winds through the channels within our body. The purpose of the completion stage is to awaken one’s consciousness by checking its uncontrolled movement. Meditation on the winds and channels is a rapid and forceful method of accomplishing such a goal.