I'd totally be the bottom chick in this scenario... hell, I'd be the top chick too... we can take turns! lol A guy friend of mine and I chat about similar fantasies often... I love the open minded free spirits I do I do!! lol
Its not much of a secret fantasy if we're putting it on blast... but I often find myself dreaming of a gangbang, it's one I've thought about crossing off my "Fuckit List" several times, but have never done the legwork to line it up.