I have a huge fic I'm working on that uses a Dick/Babs/Kory threesome as a jumping-off point. It's a bit heavy-handed in setting it up, but it comes from me wondering what it does to the relationship of two hitherfore monogamous characters to suddenly have a third party entering into their sex life, even once. Because you know me, I cannot settle for "and then they and their unresolved issues lived happily ever after."