Isn't "motherfucker" a bad word? Why he suddenly put this word in this cheerful song?
Native speaker’s answer
Rebecca
Yes, it is indeed a curse word. Bruno Mars has never explained why that line is in the song and it is actually a huge debate online as to the meaning. The main thought is that since Bruno calls his fans squirrels quite often, and no one really knows why, it is a reference to his fans. Often, in informal conversation or slang people will use curse words as intensifiers for adjectives to add emphasis. This seems to be the case here.