Bandhas are necessary for practice of Pranayama, Bandha means energy lock. There are main 3 types of locks, first is Jalandhar Bandha or Chin lock, second is Moolabandha or anus lock and third is Uddiyan Bandha or abdominal lock. These locks are essential while doing the Kumbhaka that is retaining the air inside or outside of the lungs. During Pranayama, these three Bandhas are used,
Mulabandha-Root Lock
Uddiyana Bandha-Upward Abdominal Lock
Jallundhar Bandha-Chin Lock
Creative Energy Generators
After you have mastered the energy locks you are ready to incorporate them into more complicated techniques that are the core of tantric practice:
Aswini Mudra
Vajroli Mudra
These practices both generate intense energy in the lower body while keeping it contained. This builds up pressure in the energy channels. Once the containment is released, that pressurized energy shoots up the spine, breaking through any blocks or restrictions.