I was able to get this trophy in just one battle, the boss battle against Jimmy. During my opening turn, I consumed a large mana potion (which caused the “Irritable Bowels” trophy to pop). After that, I pulled my punches (didn’t fire or swing during combat), keeping Jimmy alive long enough for him to repeatedly use his “Brown Note” ability. This trophy popped after the second time Jimmy used the ability on me.
Good luck! Don’t forget a change of clothes!