You're sitting on the couch. There's a baby playing on the floor. Suddenly a whiff of stinky air rises from the rear section of the baby and hits your nose. You decide to check his diaper, only to discover there is no poopy.
To be Mommy, jump down one line. To be Daddy, jump down two lines:
Mommy: "Oops! No poops, just tooters!"
Daddy: "There's no crap; it's just some trapped gas."