The only thing I can think of is many many years ago the late great Johnny Cash had a famous and kinda controversial song a "Boy Name Sue."
Never heard of it
I've never heard of that either but it might be referring to the song Jan said although I've never heard it said like that!
My parents said my new nickname should be Sue. When I asked what it meant, they said it meant a grown man. I'm thinking it might be some kind of older person type of speak. They're both in their 50-60s if that helps.