Silverlight Terrace you can check

Ignoring the suggestive gaze from Tuvaq, Abaddon was not one to feel jealous or care about these silly little games. He just happened to come up on this scene and thought it would be humourous to take a bite out of his sometimes companion's ass just for the hell of it. 

I don't think we decided on a term - I fuck him, he fucks me, we fuck other people. He pauses mid-stride to offer a deep shrug. That's the gist of it I suppose. Finally, he comfortably places himself among the other two, not behind anyone, but among them to see what might transpire before moving on.