A little boy walked in on his parents having sex and asked what they were doing.
His father replied, "Well, you know how you've always wanted a little brother?
That's what I'm doing--I'm putting a little brother in your mommy for you." The
little boy nodded gratefully and left the room.
The next day the father came home from work and the little boy was on the front
porch crying. When his father asked what was wrong, he replied, "You know how
you put a baby in my mommy last night? The mailman came to the house this
morning and ate him!"