[ChenWangHu]

The "Google Dance" is a term that refers to Google doing an algorithm update or a data refresh. It has nothing to do with what you are doing to your website, you have no control over it, there is nothing you can do to cause it or to prevent it. It's useful to be aware of it simply to prevent unnecessary worry or reaction.

From my own experience, Google dance happens when you don't build your link consistently...

Is either Google see a spike of links in today, and the next day zero, it might trigger a dance! However, this doesn't mean it is a bad thing, because when your page is back, it will rank a lot higher than before - thanks to all kinds of authority backlinks!

I had a rule myself, I don't do any on page optimization when my site ranking drop, because I did it few times my sites were filtered for a whole month!