The Legend of Korra

I thought it sounded like he called it Boogie.

I almost want to go back and find it, so I can turn my speakers up and hear what he called it.

Regardless, it still leaves the question of...where did more Flying Bisons come from? I thought that Appa, like Aang, was the last of his kind. The only difference is that Aang didn't need another Airbender to make more Airbenders...but I'm pretty sure Appa would have needed more Flying Bisons to make more Flying Bisons.