A gay guy walks into a straight bar, and the barkeep says "hey, i know you're gay, i got no problem with that. Just don't go to the bathroom, 'cause you're just gonna go jerk off, and i JUST painted the walls."

"Whatever." the gay guy drinks a few beers, watches and talks to some people. He's gotta go take a leak. He waits for the barkeep to be busy, and sneaks off to the bathroom"

Seeing neither the gay guy, or a paid bartab, the barkeep knows, the guy is in the bathroom. He runs back, just as the gay guy comes out of the bathroom.

The barkeep peeks in the bathroom, and discovers cum literally all over the walls. "Dammit, i told you not to go in here, I knew you'd jack off."

Insulted, the gay guy replies, "I didn't jack off, I farted."