What is Never Rub Another Man's Rhubarb!?
1.
Yes, its from the first Batman movie in 1989. It means stay the fuck away from my girl. It is part of the code. No friend of mine is allowed to talk to or hang out alone with my girlfriend unless they want the wrath unleashed upon them.
"What the fuck man? You took her out to dinner last night? Never rub another man's rhubarb."
See
2.
Told to Bruce Wayne by the Joker. The Joker was refering to his relationship with Vicki Vale
"Never rub another man's rhubarb!"- The Joker(Jack Nicholson)
3.
Can be used in two cases. One for the girls and one for the guys. When this is said to a girl, it means dont play with other blokes
Boys: Hey man, thats my girlfriend you're trying to impress. Stop it, never rub another mans rhubarb.
Girls: Hey there bitch what you doing? That guys coming on to you. Remember I'm your boyfriend, never rub another mans rhubarb or else. (fight)