Homosexual anal sex. The term pissin on hoes represents the relationship with the penis and the male anus hole. Unlike women, men have a distintive gland that produces a urine/sperm combination fluid that is ejaculated when the climax, or orgasim, is reached. This urine/sperm unification was what coined the term "pissin on hoes".
Doctor: Have you ever engaged in homosexual intercource of the anus Arthur?
Arthur: I have been known to be pissin on hoes once in a blue moon Doc.
Doctor: I see Arthur.