"You don't have any of these..."
This little boy and girl were playing doctor one day, when the boy pulls down his pants and says,
"You see what I have? You don't have something like this!"
So the girl picks up her dress and says, "You see what I have? With one of these, I can get as many of those as I want!"
Found at
http://your-joking.atspace.co.uk/