Reminds me of that one where a blindman is standing at a street corner, with his guide dog, waiting to cross the road.
Suddenly for no good reason, the dog cocked its leg and peed all over his master's trouser leg. The blindman then began fishing in his pocket, looking for a biscuit to give to the dog.
A passer-by has observed this and says to the blindman : The dog's just pissed on your leg and now you're giving it a biscuit?
Says the blindman, : I'm just trying to find its mouth mate, then I'm going to kick it in the bollox!