Not sure this is a fetish but I find a gangbang a huge turn on. But it has to be with a non-WG, I've been to WGs gangbangs and they don't turn me on as much as civvies doing it. I think I got the taste years ago during one of my BDSM and swinging days, a young woman organised a gangbang for herself. I was very lucky to be selected, think there were about 8 or 10 guys. She had two minders, another woman (who didn't participate) and a man (who participated).
We were given the safety rules, (red, yellow, green safe words), what we could and couldn't do. Apart from scat and blood everything was allowed, no holes barred, as long as we were aware of her safe words. There was a rigger as well who tied her up to start the session, followed by extreme spanking then we were allowed to go full legalporno on her. Only once she said yellow when she was being double penetrated (can't remember if it was vag or anal). We were told to try and save our cum for the end, very hard, but we finished with bukkake and then pissing on her (I didn't do the pissing, not my thing).
Been trying to go to another organised by other civvy girls but the vetting is very tough, a lot of them prefer gangbangs with fit young men, I'm no longer a fit young man (in fact I never was). To this day I think that was the best gangbang I've been (and I've been to a few).