A drunk gets up from the bar and heads for the bathroom.
A few minutes later, a loud, blood curdling scream is heard from the bathroom.
A few minutes after that, another loud scream reverberates through the bar.
The bartender goes into the bathroom to investigate why the drunk is screaming.
"What's all the screaming about in there? You're scaring the customers!"
"I'm just sitting here on the toilet and every time I try to flush, something comes up and squeezes the hell out of my balls."
With that, the bartender opens the door, looks in and says... "You idiot! You're sitting on the mop bucket!"