I like the term “derriere” borrowed from the French. It is the most pleasant and dignified (actually flattering) way I know of to refer to the human bottom, or whatever you call it depending on your upbringing and socialisation.
You can inoffensively refer to your mother-in-law’s derriere in her hearing; I don’t know which other word you can do that without coming off as a despicable character.
Different cultures have their…


