Songfacts®:

• Here, Melanie Martinez sings about feeling vulnerable in the early stages of a relationship. She wrote the song with fellow New Yorker Emily Warren, whose other songwriting credits include Shawn Mendes' "Aftertaste" and Sean Paul's "No Lie." Warren has since becoming a frequent collaborator with Chainsmokers, co-writing their hit "Don't Let Me Down" and singing on "Paris."
• Martinez explained the song's background to Elle magazine: "Soap was written about my current boyfriend when we were first talking, I felt too scared to say how I felt about him and thought if I told him it'd be like throwing a toaster in his bath. So I washed my mouth out with soap. I think anyone can really relate to this song. I'm sure there was a time in everyone's life where they felt too scared to say how they felt so they 'washed their mouth out with soap.'"
• Emily Warren recalled the session that produced this song in an interview with Pop Crush: "Melanie was having some problems with a boy at the time, debating whether or not to tell him that she had feelings for him, and playing out the consequences of rejection. We came up with the idea of washing your mouth out with soap as a metaphor that also fit within the theme of her album. Then with the bubble drop… we just couldn't resist."