[@Spriggs27]
You don't need a butt to poop. A butt is simply the cheeks, plenty of animals can take shits without a butt.
However they do need an anus, which is the opening required to take a shit. An asshole if you would. There is a difference between an anus and a butt.

Also I doubt their culture is like that at all XD But what Vesta doesn't know won't hurt Zin XD