Vipers and SE

Does stun mastery work while activating like Double Upper,BEFORE the monster is stunned?I dislike the words in your sig,you know hecka stuff >.<

I think this is what you are asking: If you attack an unstunned monster with a stunning move, will it crit on that attack?

The answer is no. The mob must be stunned before you use an attack in order for that attack to crit (unless of course you have SE, but then that goes back to the debate in this thread lulz)