An old guy...

An old man is walking in Amsterdam and passes a hooker standing at her door.

She asks him: "Granddad, why don't we give it a try?"
He replies: "No girl, that's no longer possible for me."
Says the hooker: "Come on, what have we got to lose, we can give it a try!"
They both go inside. They undress and he performs like a young buck, 
giving it to her 5 times in a row.
"Oh my goodness", says the hooker, breathless, "and you said that it 
was no longer possible for you?!"
Says the old guy: "Oh, screwing is still going well, it's the paying 
that is no longer possible!"

Moral of the story: Don't mess with seniors.

Thanks Randy