If you want to short safely, my recommendation is to do it only if the following conditions are simultaneously met:
1) VIX reaches very high historical levels
2) Both 1st and second month futures are very high and backwardation starts to clearly reduce or even alternate with some days of contango.
Even then you are never sure, since it could be you short under those conditions and then the VIX breaks a new record, but if the 2 conditions are met it will be quite improbable that the VIX, 1st and 2nd month go higher (since they already would be at historical highs).
So it is ideal to short at that time and simultaneously hedge the short.
You should scale your short and short several times small amounts to reduce the timing risk.
You should be prepared (hedged) to hold for long, it could be that the fear and backwardation re-surges or stubbornly remains high. It will go down on the long term, but make sure that the fear does not remain longer than you can remain solvent (or margined out)!
It could very well be that 1) and 2) do not happen, in that case the short has a smaller probability to be successful and you should consider seriously if you should do it and how.
If 1) and 2) do not happen you run a risk of shorting too soon (with all it’s nasty consequences). So in such case it becomes important to hedge your short, at least partially if conditions 1) and 2) are met and if not you should hedge even more.
I shorted a “small” amount (compared to my goal) because only condition 1) was met so I hedged it 100%, if condition 2 happens (we are closer to it) I will short more and hedge less.
PD: you can download here the historical VXX data (since 2004 when vix futures started to be traded) that supports the evidence that 1) & 2) are good shorting periods, I highlighted the shorting periods in it.