Since I'm drunk and apparently about to go over and knock out my friend's ex, I'll give the short version of how I slept with my other friend's ex, and how it only involved anal sex.
We were playing trivia at a bar one night, and this question came up- Who were the Mexicans fighting when they won their independence on Cinco de Mayo? Well, I of course knew that it was the French. She, however, is SURE that it's the Spanish. So we're pretty drunk and we argue, and it's time to turn in an answer and she blurts out "I'm turning in the Spanish, if it's the French you can fuck me in the ass!" My friend, seeing as how their relationship was always insane, just kind of shrugged.
So of course, the answer comes back "The French". I start laughing and giving her shit about it the whole night, threatening to not use lube. I'm only joking. Anyway, about two weeks later they go through one of their infamous month long break ups, and in the middle of that I run into her out at a show. She's there with friends and is getting progressively drunker. I'm my usual self, and don't mention anything about our silly little wager. But at the end of the night, she grabs me and says "Let's go work off that bet". I had always known she was crazy, but I found out how crazy she was that night as we did about two grams of coke and I fucked her in the ass- she wouldn't let me fuck her in the vag, saying "We didn't bet on that!"
Anyway, they got back together a few weeks later and she told him about it when they broke up for good like six months later. He was understandably pissed, but got over it.
Point is- I guess I hang out with fucked up people. Now I'm gonna go have sex with another one of his exes, I suppose.