vag pals
Where a guy and a girl have done the same girl at some point in time; not necessarily a menage a trois
Guy Carl sleeps with girl Suzie; the next week Suzie sleeps with the girl Betty. Carl and Betty are vag pals.
Vag pal
A close relationship between two heterosexual females or the female equivalent of a bromance
Cathy and Heather and really into each other. They are such vag pals.