Mastodon is big in Japan, and the reason why is uncomfortable
"Uncomfortable" as in "offends my American puritan-inspired sensibilities"."Pardon him, Theodotus: he is a barbarian, and thinks that the customs of his tribe and island are the laws of nature". George Bernard Shaw, "Ceasar and Cleopatra".(Slightly off topic: Feynman had a nice story in one of his books about how the main in a Japanese guesthouse he stayed walked in while he was naked and having a bath. She didn't flinch and just went on about her business like nothing had happened, and he was thinking what a fuss/embarrassment etc that would have caused if it happened in a hotel in the US -- when it's just an adult being naked with another adult present. It's not like everybody hasn't seen genitals before or it's a big deal.)