Little Boy's Knowledge

A little boy walks into his parents room to see his Mom on top of is dad bouncing up and down. The Mom sees her son and quickly dismounts, worried about what her son has seen she dress's quickly and goes to find him.he son sees his Mom and asks' "What were you and dad doing?" The mother replies "Well you know your dad has a Big tummy and sometimes I have to get on top of it to help flatten it. "Your wasting your time." say's the boy. "Why is that?" asked his Mom, puzzled. "Well when you go shopping the lady next door comes over and gets on her knees and blows it right back up."