I read the chin pump several times but am still not clear about the method. Let me summarize my understanding.
(1) You have the chin down touching the chest. Then take a root to brow deep breath (2) Hold the breath. (3) Move the head in a circle from left to right and then let in fall to the chest. (4) Keeping the chin at the chest exhale from brow to root. Then inhale from root to brow. all this while the chin is at chest. (5) Now move head in circle from right to left and let in fall to the chest.
The head never stops. Lets say for example you start with your head turned to the left while breathing in from the root you swoop your chin down toward your chest and then up to the right back across to the left and then swoop down and up to the right again, imagine you are drawing a circle with your chin. You continue this until your breath reaches your brow, at that point you hold your breath and at the same time reverse the direction of the swooping movement. Holding your breath for a comfortable time and still making the circular movement your chin still going in the same direction you breath out to the root and then back up to the brow again, at the brow you retain your breath and reverse direction again and so on and so on.
Yes, I agree with Richard however I find in my practice that the head may sometimes pause at any phase of the circle and thats fine. I let the energy of the breath iteslf determine the speed of rotations rather than any particular rythm. In my case it can often be paistakingly slow as the breath slowly releases deeper areas, or sometimes not as slow if it isn't going as deep at that moment but the guide is the internal energetic action of the breath.Sensitivity is the key