In the tantric texts, kundalini is conceived of as the primal power or energy.
Note that energy has no shape and size.
In terms of modern psychology, it can be called the unconscious in man.
In shaktism, kundalini corresponds with the concept of Kali.
In the philosophy of Shaivism, the concept of kundalini is represented by the shivalingam, the oval-shaped stone or pillar with a snake coiled around it.
However, most commonly, kundalini is illustrated as a sleeping serpent coiled three and a half times. Of course there is no serpent residing in mooladhara, sahasrara or any other chakra, but the serpent has always been a SYMBOL for efficient consciousness. In all the oldest mystic cults of the world you find the serpent, and if you have seen any pictures or images of Lord Shiva, you will have noticed serpents girdling his waist, neck and arms.
Kali is also adorned with serpents and Lord Vishnu eternally reposes on a large coiled serpent. This serpent power symbolizes the unconscious in man.
In Scandinavian, European, Latin American and Middle Eastern countries and many different civilizations of the world, the concept of the serpent power is represented in monuments and ancient artifacts. This means kundalini was known to people from all parts of the world in the past. However, we can conceive kundalini in any manner we like because actually,Prana has no form or dimension, it is infinite.
In the traditional descriptions of kundalini awakening, it is said that kundalini resides in mooladhara in the form of a coiled snake and when the snake awakens it uncoils and shoots up through sushumna (the psychic passage in the center of the spinal cord),.
The meaning of the 3 1/2 coils of the serpent is as follows: The 3 coils represent the 3 matras of AUM, which relate to past, present and future; to the 3 gunas: tamas, rajas and sattva; to the 3 states of consciousness: waking, sleeping and dreaming; and to the 3 types of experience: subjective experience, sensual experience and absence of experience. The 1/2 coil represents the state of transcendence, where there is neither waking, sleeping nor dreaming. So, the 3 1/2 coils signify the total experience of the universe and the experience of transcendence.
Ref : Kundalini tantraFeatured image by eddie howell on Unsplash