Before being able to fully understand Chan Si Jing (or "silk reeling" jing), you have to be able to keep constant flowing motion. That said, constantly flowing in one direction is not Chan Si Jing or spiraling- you have to be able to change directions. For this, the classics talk about "left before right, right before left" as well as "up before down" and so on.
These might sound intrinsic to how we move naturally- people tend to "load up" before they punch- but that is not what this conveys. To have this quality and get the benefits from it, you have to maintain constant flow and motion. That means you can't stop when you change direction- but have to keep flowing.
This can be thought of similarly to the "electric" and "magnetic" switching jings, but instead of getting power from the sudden switch from extreme to the other, you flow through all of the middle points smoothly.
The effects are also very different. While the harsh switching between extremes causes Fa Jing style explosive hits, this quality lends itself to much more refined motion and control of whatever you are touching or whoever is holding on to you. While the switch will throw someone off of you and force them to seize up, this quality does not generally cause the same seizing, and others will find it difficult to hold on to you at all. They may end up tweaking or even breaking their own wrists/fingers just to hold on. The famous Chin Na of Tai Chi benefits heavily from this concept, and you will find new opportunities present themselves when you can move properly.
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