A few fans thought that the hidden meaning of the song was about Jon and Richie's relationship IE: "You could sing a melody for me and I could write a couple of lines" etc etc.
But IMO there are just too many mentions of the word "baby" for it to be this.

I know JBJ and RS like each other, but come on, I couldn't see them calling each other baby!!!!!!!!!!

Never agreed with this theory. I think it is Jon catching up with an old flame (most likely female!).