Up

A number-one single. Cardi explained to Jimmy Fallon, on national television, that the hook's central phrase is a metaphor for a bowel movement that gets stuck partway and won't come out. The audience was not ready. Fallon was not ready.

This makes 'Up' the only song on this site whose poop meaning was revealed on a late-night couch, and the sole holder of the Constipation category's top spot.