The fifth step or limb is called pratyahara and is defined as “the conscious withdrawal of energy from the senses.” This limb starts to internalise the mind.
To explain pratyahara think about relaxing in Shavasana (Corpse Pose). The first stage of shavasana involves physiological relaxation. In this stage, as you become comfortable, there is first an awareness of the muscles gradually relaxing, then of the breath slowing down, and finally of the body completely letting go. While deeply relaxing, this first stage is only the beginning of the practice.
The next stage of shavasana involves the mental “sheaths.”
According to yoga philosophy, each person has five subtle layers of consciousness. In the second stage of Shavasana you are withdrawing from the external world without completely losing contact with it. This withdrawal is the experience of pratyahara. It feels like you’re here, but not here. For example, you notice the sounds in the environment, but your mind and body are not disturbed by these sounds. Pratyahara is this state of non-reaction. You still register input from your sense organs, but you don’t react to that input. You are simply witnessing and watching the sounds.
Ultimately, the practice of pratyahara will enable a person to choose their responses instead of merely reacting to the environment. We can choose to dance with any stimulus that comes our way, or we can choose to step back and consciously not respond to that stimulus. We can be in control of our reactions, remaining in the middle of a stimulating environment and consciously not reacting, instead choosing how to respond.