butter someone up
phrasal verb with butter verb [ T ] uk/ˈbʌt.ər/ us/ˈbʌt̬.ɚ/
informal
奉承…;拍…的马屁
to be very kind or friendly to someone or try to please someone, so that that person will do what you want them to do
You'll have to butter them up a bit before they'll agree. 你得奉承他们一下，他们才会同意。