Brawlout

The other guide says a KO is the 3rd knockout. This isn’t true, a KO is simply a kill move. In other words a KO is when you hit the opponent and he gets knocked off screen.

To use it spam in the air while holding the analog stick forward (in the direction you’re facing). Technically the move is done with pressing x,x,x. You have to hit the 3rd x which is an overhead kick. The second x is an overhead kick as well but it must be the third kick

You need to forward jump and hit x 3 times. The third one is a overhead kick and it need to knock the other player off the map. Suppose to be a KO (3rd knockout) but me and my boosting partner both got it on the 2nd one.

Thanks to Irishwarrior22 and Shizblacka for figuring this out.