The books describe a fire that sleeps at the base of the spine in every human being. The traditions of the East call it Kundalini, the coiled one. It is often pictured as a serpent.
When the creative energy is kept and raised over a long time, this fire begins to wake. It climbs the spine slowly, from center to center. As it rises, the books say, the faculties sleeping in each center wake, and the person changes from within.
Here is what much modern teaching leaves out. The fire is not a technique, and it is not yours to force. The tradition calls its power the Divine Mother, the same power you asked on page 31 to take a self from you. She raises it. Your part is to prepare the ground.
She raises it according to what she finds. The books say the fire climbs according to the merits of the heart. A person who keeps the energy but stays proud, cruel or dishonest does not rise far. A person who keeps the energy and works on the selves of Part II, with a sincere heart, rises.
So be wary of anyone who promises a fast awakening, and of practices that force it with strain. Fire that is forced burns. Real progress here is slow and quiet, and it is bound to the rest of the work.
You do not need to feel the fire to begin. You only need to keep the energy, work on yourself and ask.