I heard the late Bob Cooney sing this at Aberdeen Folk Club some 30 years ago. He had a book of his songs and poems printed which I still have, I think. I'll look and see if it's in there.
"Rosia Rum", I think he used to sing - don't think it means anything in particular. And the song - or at least Bob's version of it - did mention Coca-Cola, which might date it a bit.