The fifth limb of Patanjali’s path is the withdrawal of senses. Pratyahara is conscious control over taste, touch, smell, sight and hearing. More succinctly, it is control over the reaction to those senses. Pratyahara is refraining from reacting to that which cannot be controlled. It is separation of the self from goings-on in the vicinity.
The hardest part of pratyahara is avoiding reaction to social stimuli.
The easiest plan would be to retreat to a cabin in the woods where there is no social stimuli, but to truly practice pratyahara (and all eight limbs), yogis must immerse themselves in the world and learn to control their reactions to what is happening all around.
There will always be stimuli, both annoying and pleasurable. Pratyahara is the fifth step in controlling reaction to external stimuli and becoming blissfully present without needing to judge or control.
Furthermore, pratyahara is the emotional wherewithal to endure life’s ups and downs without constantly seeking distraction. By controlling reaction, yogis can avoid seeking distraction.
Pratyahara is the subtle application of the first four limbs. Living an honourable life (yamas and niyamas) and practicing breath and body control (asana and pranayama) contributes to withdrawal of reaction (pratyahara).
Once the senses withdraw from the objects and imitate the mind-stuff, this is pratyahara.
-Yoga Sutra 2.55
