This is clearly a song about going through a breakup, and I think it’s one of Martin’s best from the Poppy Salesman album.
He paints the picture of a person who suddenly finds they are alone in a home they had shared with a partner for some time. You get the impression of a person sitting in shock on the sofa, taking inventory of their life. They aren’t ready to move on, but by the end of the song they know that they have to.
The song also showcases Martin’s knack for using sort of silly lyrics in very serious moments. “Little brown poos from a little pink bum” doesn’t seem like a phrase you would find in a song like this, but it works.