time to short or not

Having read posts in last thread, it seems that one question is in everyone's mind, should I short it right now?

Several posters including very experienced seem has done it already, maybe fear the chance is too good to miss. There is hardly any 200 points daily rally in the past.

But in the past, the market always ended up a lot higher a few days after similar powerful move.

I don't know whether it is a good idea to do so.