All you have to do is do your KO punch OOS after you've been hit, it's almost instant since there is no shield lag in SSB4.
And since the KO-Punch comes out so quick, there's no time to react to it. It reminds me a lot of rest OOS on Jiggs in Melee.
And since the KO-Punch comes out so quick, there's no time to react to it. It reminds me a lot of rest OOS on Jiggs in Melee.