I don't exactly know how we got on the subject but somehow over the course of the night we started talking about bestiality. I think it was because she said some sort of sex act didn't count and I jokingly asked her if she though that having sex exclusively with animals made you a virgin, and she said yes (I disagreed). I pressed on and asked why, and she replied simply that it didn't count.
This launched a huge philosophical discussion that ended with a burst of laughter and my scenario
"Well what if a horse rapes you? Is that the same thing as a tree falling in a forest?"
Apparently it is.
Then that lead to a discussion about bestiality vs. other sexual fetishes/disfunctions etc. and I had to vocalize my qualms with some of her preferences in the bedroom.