I remember this Mii in Mario Kart 8. However, the reason it is inappropriate is because it looks like... uhm... idk how I could say that.... the part of human body when we fart?

Just make sure next time you don't make an inappropriate Mii.

Also (out of context but want to say that) I say to you as a christian that Jesus loves you. I personally found peace and joy. I respect everyone's opinion, but I still wanted to show you some of my faith ;)

Butt. It's because the mii looks like a butt.