Character I used- Johnny Gat
First of all, I would say boost this achievement. Getting it legit can be pretty difficult. Anyway, in order to activate Kickfactor, all you have to do is kick. Alot. Your Kickfactor is the red bar in the corner of the screen. Once this gets filled, it will automatically activate.
Now, the easiest way to fill it up is to do short kicks and rotate wins this way the match doesn't end. Now, once the meter is almost filled, win a round with a headshot. Next round immediately kick to enter kickfactor. Your character will be glowing red. The person going for the achievement must kick the player in Kickfactor while they are still dizzy. It's a pretty tough achievement, so don't be mad if you don't get it on the first try.
Please comment or message me if you have a question.