Kundalini

Ida, Pingala, and Sushumna are the three principal nerves. All the lotuses are located in the Sushumna. They are formed of Consciousness, like a tree made of wax-the branches, twigs, fruits, and so forth all of wax. The Kundalini lies in the lotus of the Muladhara. That lotus has four petals. The Primordial Energy resides in all bodies as the Kundalini. She is like a sleeping snake coiled up of the form of a sleeping snake, having the Muladhara for Her abode.

(To M.) The Kundalini is speedily awakened if one follows the path of bhakti. God cannot be seen unless She is awakened. Sing earnestly and secretly in solitude:

Waken, O Mother! O Kundalini, whose nature is Bliss Eternal!

Thou art the serpent coiled in sleep, in the lotus of the Muladhara.

Ramprasad achieved perfection through singing. One obtains the vision of God if one sings with yearning heart.

                        - Gospel of Sri Ramakrishna, P 362-63 

                              (24 December 1883)