This is practiced with opposite feelings such as heat and cold, heaviness and lightness, pain and pleasure etc.
You are instructed to release the feelings of heaviness to the maximum extent followed by the feeling of lightness to maximum extent.
The similar instruction will be given for the feeling of heat and cold.
This feeling of opposite sensation integrates left and right hemispheres of our brain which helps in balancing our basic driver and controlling function.
This stage also develops will power on emotional plane.