Why the Microcosmic Orbit?
Like the pattern of nature, Taoists seek to have balance throughout the system. The microcosmic orbit promotes balance within the body by mixing the hot and cold, or yang and yin energies.
The orbit is comprised of two of the main energy meridians of the body. These are also called vessels, channels, or even ‘great rivers’ of energy. The governor vessel travels up the spine, from the perineum to the roof of the mouth. The conception vessel travels up the front, centerline of the body, to the tongue.
When the tongue is placed at the roof of the mouth, behind the front teeth, the two channels are connected, forming a loop or orbit. This typically causes the energy to flow up the spine and down the front of the body, although sometimes it is experienced coming up the front of the body and down the back.
From The Alchemist’s Tao Te Ching: Transforming Your Lead Into Gold https://www.amazon.com/dp/1718636970/ref=cm_sw_r_cp_api_i_o2zAEbNJ1EKRE