Celibacy is to a Yogi what electricity is to an electric bulb. Without celibacy no spiritual progress is possible. It is a potent weapon and shield to wage war against the internal evil forces of lust, anger and greed. It serves as a gateway for the bliss beyond, and opens the door of liberation. It contributes perennial joy and uninterrupted bliss. It is the only key to open the Sushumna (the chief among astral tubes in the human body running inside the spinal column) and awaken the Kundalini (the primordial cosmic energy located in the individual).

http://www.dlshq.org/teachings/brahmacharya.htm