go piss girl is from a meme of a series called gossip girl. i always have to pee, but my best friend never has to. so if i have to pee i just tell her that and she says:„go piss girl“. it‘s an inside joke for us.
It's like " go take a long walk on a short pier". It would be very hard to piss up a rope. It's also like telling someone to "fuck off" or "go get lost". A widely used term in the 50's and 60's by men who worked in factories together for extended periods of time.
Shakey was so mad at Ralph that he told him to "go piss up a rope". Ralph was so stupid that he actually obtained a large piece of rope and proceeded to urinate on it while it was held in a vertical position.
one friend: *lead actress in a broadway production and in the middle of a scene on stage in front of thousands* how can i ever learn to love again???
other friend: *shouts from audience while the whole room is quiet* GO PISS GIRL