When BOY eats something and poops it out of his bottom, you can hear the name of the things that he pooped out. That is a new feature that we implemented, and that we call Fart BOY.
For example, when BOY poops out a dog, you can hear "dog" or "inu" [note from the translator: inu means dog in Japanese]. The name of the things BOY pops out is told in English or Japanese in a random way.
That way people will also learn Japanese!