>>531350803
If you attempt to deal damage, try to wait until you have a full gauge and do it in the following order:

Satsuki 6 cost >instantly iWappi and instantly jkAsuna then Satsuki 6 cost again, you should be able to fire off two EX's at max boosted by the buffs this way, provided you have dealt with the radiator and hypothermia mechanic.
Try to get the timing down and check the pause menu to see if your buffs last long enough to fire 2 times.