Feel this page would benefit greatly from a video or diagram. "Tumbled over and over in a circular motion between the two hands" can be a bit hard to interpret if you aren't already familiar with the motion being described. Does this circular motion involve rotating the shaker a complete 360 degrees, and if so is it being turned like a cement mixer or being flipped end over end? What should the orientation of the shaker be while doing so? Do you hold the shaker by the ends or in the middle?
Previous copy on this page was confusing, to say the least. I've updated so now hopefully more self-explanatory. Many thanks for bringing to my attention.