I was just practicing it with the damage turned off and it's fucking hard. At least for me, my timing sucks. I only got the triple fireballs twice in like 20 minutes of trying. Only got the double fireballs to work about 25% of the time and the single fireball about 75% of the time. A lot of times I waited a little too late, missed the JK and went right into the fireballs on the landing frame. My timing sucks.