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 extra words.
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.