Once can contract the frontside of the body with the dantien/hara as center to 'close' the body. One can also contract the backside of the body, again with the dantien/hara as center to 'open' the body. This opening and closing of the body can only be done if the internal connections of your body have been conditioned sufficiently to guide the movement. And if you allow these connections to fully define your movement, you'll get the typical spiraling movements of silk-reeling.
(Bolding added by me...) Good point - I hadn't been explicitly formulating it that way, but in the body was certainly feeling
it that way.