So a few years back we're walking down the street and there are these 9-year-old girls with ukuleles playing Brand New Key, and I say, "That's a pretty dirty song for those kids to be singing." My friend says, "What are you talking about, that is a completely innocent song." Then later that night we see The Dollyrots, and they play it too, and my friend says, "Ok, you're right, that song is dirty as hell."
yup.
https://en.wikipedia.org/wiki/Brand_New_Key#Controversy
"Melanie has acknowledged the possibility of detecting sexual innuendo in the song, without confirming or denying the intent:"