When I was younger, I was always jealous of the other Asian kids. Why? Because they had kick-ass unarmed martial arts. A Chinese kid could say "Hey, don’t mess with me - I know Kung Fu like Bruce Lee!" What was I going to say in response - "Well, I know Ahimsa like Gandhi?" [Link]
How about: "I'd love to fight, but I've got to get busy with my girlfriend."