Scream

A drunk gets up from the bar and heads for the restroom. A few minutes later, a loud, bloodcurdling scream is heard. A few minutes after that, another loud scream reverberates through the bar.

The bartender goes to investigate why the drunk is screaming.

“What’s all the screaming about in there? You’re scaring my customers!

“I’m just sitting here on the toilet and every time I try to flush, something comes up and squeezes my nuts.” 
With that, the bartender opens the door, looks in and says,

“You idiot! You’re sitting on the mop bucket!”