This trophy can be done in practice mode or versus.
Select "Fallen Garden" as the stage.
Set the A.I to offensive (If you're choosing to do this in practice.
Have the A.I or friend knock you down to the floor.
The trophy should unlock once your character is doused in whatever it is on the floor.
If it doesn't immediately try rolling around on the floor by pressing either Square or Triangle.
If anything needs changing please pm or notify me via psn.