"Dou Dou" is Haitian Creole for "Little Darling" and it can be a way to address a woman but it is also sometimes a nickname for a man. I think, given that they are Yellow (Creole) Girls working at Madame Gashee's, the Haitian endearment is probably the origin of sailors addressing them as "Doodle." Great song, anyway, good stamping rhythm for a capstan shanty.