Pranayam.
The mind follows the breath. The key to controlling the mind is in controlling the breath. A kundalini yoga class is not just a series of excercise that stretch or stimulate the body. Kundalini yoga moves energy and pranayam is the most vital tool in this process. Breath awareness requires conecntration. It brings attention to the vital link to life. The breath regulates the energy of life, the quality if emotions and the ability to direct the mind.
Pranayam is when you want to expand yourself. Your power, your psyche, your intuition or your uderstanding.