Biggest sex kink/turn on?

For me it's fire. I like to be lit on fire, or to light girls on fire during sex.

I knew a girl who liked this too, and she also had a rape fetish. More than once i raped her and set her on fire. She'd return the favor, setting me on fire and making me cum while i burned. We'd wear a few layers of shirts when we'd play, douse each other in alcohol or lighter fluid, and light up.

We'd also douse both of our shirts, and when we'd light ourselves up we'd both cum instantly, while we were both on fire.

Yes, it's dangerous, and yeah, we'd get burns, but it's worth it and part of the fun.