Kundalini yoga is Raja of all yoga. The Kundalini is untapped energy (prana) at the base of the spine that can be drawn up through the body awakening each of the seven chakras. Full enlightenment occurs when this energy reaches the crown chakra at the top of the head. Kundalini energy is often represented as a snake coiled at the bottom of the spine.That is when she who uncoils and awakens at the bottom of the spine. Kundali Yoga asana sequences are called kriyas. Each kriya is preset series of poses that is done with a specific breathing technique and engagement of the bandhas to intensify the effects of the pose. Each kriya is associated with a particular chakra. They may consist of rapid, repetitive movements coordinated with a designated breathing method or recitation of a mantra. In other kriyas, poses are held for several minutes, again with the inclusion of pranayama and mantra. Often mudras are also an important part of each kriya.
A personalized Kundalini practice would begin with a numerological analysis and diagnosis of which chakras seem to be blocked. Specific kriyas are then prescribed to help bring balance and move prana through all the chakas.
In a group class situation, the teacher will typically pick of set of kriyas that will be beneficial to most people.