Okay. I don't know if the notion will appeal to you, since it may or may not be in the spirit of "gangbang," but in my adventurous young adulthood I used to go to swing parties now and then. Usually I ended up in semi-private little nooks and alcoves (group sex is very distracting, especially when most of the people are strangers), but there were a few times I wandered into the group room, which was wall-to-wall mattresses with various couples/groups/puppy piles doing their thing. On one memorable night I wound up there when I was in a deeply receptive mood, and I ended up doing seven guys in a row, in various ways (hands/mouth/fucking). I felt like the Earth Mother Goddess, like I was channeling something sacred, all things to all men, giving and receiving at the same time. It was, in its way, one of the more powerful spiritual experiences of my life.

Anyway, I don't know if that helps you at all, but I thought it might give you a different perspective on the act as empowerment rather than victimization.