A kid came home from school and asked his dad, “Dad, I heard some kids talking about a thing called a vagina. What is a vagina, and what does it look like?”
“Well, son, before sex it looks like a beautiful unopened rose. “
“Wow, what does it look like after sex?”
“Well, son, have you ever seen a bulldog eating mayonnaise?”
This joke is included in the Black Book of Jokes. You can order it from here.