Little johnny wakes up 3 nights in a row when he hears
a thumping sound coming from his parents bedroom.
Finally one morning he goes to his mom and says,
"Mommy, every night I hear you and daddy making noise
and when I look in you're bouncing up and down on him"
His mom is taken by surprise and says
"Oh... well I'm bouncing on his stomach because he's
fat and that makes him thin again."
Little johnny says, "That won't work."
His mom says, "Why?"
Little johnny replies "Because the lady next door
comes over, after you leave, and blows him back up!"