One day little Johnny went with his aunt to a zoo.
Little Johnny pointed to a donkey that had a black and long erected penis more than 20 inches long.
So he asked his aunt what was that.
His aunt responded: “That is nothing”
The other month when he went with his mother to the zoo, they accidentally met the same donkey with his long dick.
Johnny pointing to it said to his mother: “Mommy my aunt told me that it was nothing. “
His mother laughed and said: “My dear it is nothing for your aunt!”
This joke is included in the Black Book of Jokes. You can order it from here.