When a girl has a stupidly long clit to the point that it sags like a ballsack. In some cases it may look like a penis. However, that is highly rare and almost never documented.
Tyler: Dude this girl i hooked up with said she wants to stick her clitsack in my butthole.
Mike: Dude that's hardcore. I guess she just wants to be one of the guys.
Tyler: Dude I hope she isn't.