I have a 18 month old niece, so I know. It is down right hilarious to see her actually stop playing, bend over, and "poot" and laugh. I have NO idea where she gets this weird behavior, but I have to say that out of all the babies I have been around, their poo gas ranks right up there in nastiness with some adults. Don't feed them broccolli, folks. Only makes it worse. "Ewwww!" says my little niece.