There are a number of words for buttocks in mandarin (including those in the title). In which situations should they be used? Which are medical terms, colloquial terms, etc.?
If you wanted to say to a doctor "my buttocks are hurting" which would you use? If you wanted to say to a friend "that guy/gal has a sexy butt" which would you use? If you wanted to say to a partner "the kids bum is smelling, change their nappy" which would you use?
Thanks!