Tantra means “to weave” in Sanskrit. The term derives from two words: tanoti which means “to stretch” or “to expand” and trayati which means “liberation”. Tantra is known as an inner metabolic mechanism which functions using Mantra (sound energy) and Yantra (body). The Prana (breath) is used as a inner fuel for Tantric mechanism and the nadis are the channels which flow to the crown chakra from the base chakra which makes a practitioner reach Bliss.
There are 7 Chakra in a human body in Tantric practices and every Chakra acts as a wheel of energy.
The sensual touches on the action organs of the body which act as a geometry (Yantra) starting from the root chakra (Mooladhara Chakra) helps uplift energies to the third eye (Ajna Chakra) creating a passage to reach the crown chakra (Sahasrara Chakra) to obtain oneness.
Sensual touches on the action organs of the body which act as a geometry (Yantra) starting from the root chakra (Mooladhara) is uplifted with the sound energy (Mantra) to the crown chakra (Sahasrara). There are three main Nadis (channels) which allow the flow to connect to the chakras are Sushumna nadi connecting the root chakras till the crown chakra, pingala (sun) and Ida (moon) nadis neutralising the masculine and feminine energy for Sushumna nadi.
The process is explained on the chart below.