Foiled by a Four Year Old: 

Today Ellie announced that she was going to swallow her gum. I asked her to please not do it.  She asked me why not and before I really thought about it I heard this coming out of my mouth: "Because when you go to the bathroom, your bum might blow a bubble." She got the most amused,  concerned, excited and doubtful look on her face and she said, "I I hate to tell you this, but I don't think you're right. I tried it, and my bum never blew a bubble. Sorry mom."

At least she's sorry.  :-)