The awakening and intensification of feelings is an integral part of the practice of yoga nidra. It is generally integrated with the rotation of awareness through the different parts of the body. Its purpose is to help induce deeper states of relaxation and to awaken and perhaps relive emotional knots in the mind as a means to their removal.
The six main types of feelings utilized in the practice are: heaviness, lightness, heat, cold, pain and pleasure.
These are suggested by the instructor during the practice session. You must try to clearly feel the sensations associated with the above, either in different parts of the body or one part in particular. For example, you can develop the sensation of heat and then eliminate it at will. Or you can try to remember a vivid pain and relive it. You must bring it from the past into the present and then throw it out of the mind. You create coldness and then remove it; you create heaviness and then remove it; you create pleasure and then remove it. This can easily release emotional tensions from the psyche, ones that have been locked in the subconscious mind. Feelings such as heaviness and heat are especially useful for inducing physical relaxation of the body as a preliminary to deeper states of relaxation.
Emotions, such as jealousy, anger, fear and so on, can also be awakened by remembering past experiences. These in particular are powerful in cleaning the mind of accumulated tensions.
The teacher should choose the feelings and emotions to be awakened according to the needs of the practitioner. This requires intuition.