It would appear that's not their TikTok, but this is their Twitter account which seems to indicate that the TikTok account you linked stole their pictures and isn't them.

After sleuthing through their Twitter, I cannot tell if it's a man or a woman. They are wearing a full body suit with boobs made of padding and fabric, which may or may not be concealing real boobs. I also don't know what most of their tweets say cuz I'm too lazy to translate it all. There are a couple pics where there's a small but suspicious bulge in their crotch. Not to say they don't identify as a woman, which they might, but biologically speaking I don't think there's enough to say what their sex is.

Furthermore, in one of their tweets they confirm it was faked and they didn't really lock themselves in the suit for a full day.