Shorting the equity index requires very strict methodology for entry. Otherwise you get the shit squeezed out of you.

I would advise you to watch for it to start crashing first. See if it can get back down to the 50 day moving average and close below it towards the end of the month. I don't think it will hold this time around.

If we have a big sell off it will occur over many days, weeks, possibly months. So no need to try and guess the top.