Prana: the breath, not the clothes

Prana is frequently translated from Sanskrit as "vital force" or "breath". It is the breath of life and the energy of consciousness in yogic teachings. Dr. David Frawley, in Yoga & Ayurveda: Self-Healing and Self-Realization, describes prana as "the master form of all energy working on the levels of mind, life and body." Pranayama (yogic breathwork) couples the poses (asanas) of the physical body with the more subtle work of the breath, integrating the physical and energy bodies.
Initially, I encourage students to increase awareness of the breath in their yoga asana practice by exhaling as they move into a posture. Exhaling ensures that the student is not holding her/his breath while in the pose.
Once that is comfortable and natural, I suggest inhaling during the extension of the torso and limbs, and exhaling while grounding the feet or other body parts into the floor. A wave action can be visualized to assist the inhale/exhale pattern.
Most importantly, the mind, the thinking aspect of our bodies, follows the breath, and does not try to control the breath.
Prana flows from the body and through the body. Pranayama is our chance to work with the breath and deepen our practice from the inside out.