Pranayama

Pranayama is the art of breathing.

More specifically, to the Expansion of Breath or Pranic Sheath Pranamayakosha the 2nd of the 5 coverings according to the Kosha Model.

Nadi Shodanham belongs to the class of exercises known as pranayama.

Aleister Crowley had his version of what he thought pranayama was:

Chapter 4 of Crowley's Eight Lectures on Yoga

Related: Aleister Crowley