Here's a fun story that relates to the current topic. This did not happen to me, but a friend of mine instead. They share this story with new people any chance they get.
The guy likes to go urban spelunking. For those of you who don't know what that is, it's basically just exploring abandoned buildings looking for things of value. Well on one of the trips he ends up finding a loaded gun, he takes the gun home and cleans it and takes the magazine out. Now they both enjoy pain in their sex lives but the girlfriend also enjoys getting fucked by odd objects. One night she decides during sex that she wants him to fuck her with the gun. They're going at it pretty good when all of a sudden the gun goes off while it is inside of her. Bullet goes straight out her lower back. He forgot to check the chamber of the gun while he cleaned it. So now she's bleeding from this bullet wound and he's just standing there in horror. Most people in this situation would go to the hospital, but instead she looks up at him and tells him that she isn't going to the hospital until he finishes fucking her and she gets off. They finish and he takes her to the hospital. She got really lucky in the fact that the bullet didn't hit anything important.
Now I enjoy pain in my sex life, but nothing in that crazy regard. It's still the craziest story involving sex that I've ever heard to this day.