I find that the fantasy of a gang bang totally gets me off...

The reality of sex with that many people, STDs and pregnancy, however, is what keeps it in the realm of fantasy.

That and finding guys that are actually comfortable working with one another in such "close quarters."

So far, I've only found them two at a time... but I like that also. :-)
Given enough time, perhaps I will slowly amass a group of like minded healthy guys. In the meanwhile, it is back to asking my lovers to fake other voices and trade out dildoes. :-)