In my practice I have discovered a refinement in the chin pump pranayama that I would like to share. It started with exploring alternate nostril pranayama using the tongue in kechari to block one nostril at a time. Combining this with dynamic jalandhara brought the question of; Is there a good or bad direction of rotation of head combined with flow of breath in right and left nostril? This led to an exploration of direction of prana during practice. This is what I have come up with: I do one full rotation per breath including retention. The inclination seems to be for the head to very gently and slightly go in the direction of the open nostril but not very much rotation during actual inhalation or exhalation, the main activity of head rotation is during breath retention with full lungs. So the breath starts with the head down centrally in jalandhara bandha. I inhale through the right nostril slowly inclinining the head towards the right side. When breath is complete I seal the throat and reverse direction gently rotating the head towards the left side all the way around the back and to the right shoulder when I naturally get the impulse to exhale, slowly exhaling through the left nostril until the breath is totally exhaled and the chin is again dropped forward in jalandhara. Then inhaling through the left noistril I continue in the same direction until the lungs are full and the head is near the left shoulder, seal the throat, reverse direction etc. Not sure if this description is clear but practicing this way really feels deeper and more balanced so I wanted to share.
Further practice has shown be that its better not to regiment how far the head rorates but just find the end of the breath ebfore reversing. With alternate nostril I find that opening the right nostril for clockwise and the left for counterclockwise seems best.