Dope duchess. With the combination of the first three letters of 'dope' added to the word 'duchess' it makes it easier to compliment one of such status without extrawords.
Bro I swear to god, she was probably such a dopuchess in her last life.
This is referred to a couple who have a very real bond, not one that's contractual or arranged. Commonly seen very much in love while dropping hints of their kinky taste.