Interesting question! I have some masochistic deeds that came from taking my masochistic fantasies a bit too far, and I have some regrets.

I have a slightly larger than average penis and I often fantasize about getting it in trouble, like crushed in a car door and ground up in a meat grinder. Of course I don't really want to lose or damage my penis, or even feel serious pain, but I do feel the urge to play these sorts of games with it, like taking risks and getting it into mild discomfort. For example, I'll stick my erection through a doorway and then pull the door so it swings closed to bash my penis against the door frame. It doesn't really hurt, but I can imagine that it hurts more than it does. I also like to have my pants open and my genitals hanging out while I work with power tools. I'll rest my soft penis on a piece of wood while using a drill on that same piece of wood. I try not to get too close, but the danger is exciting.

Another interesting thing to do is jump on a trampoline and do what's called a "front drop" where you land on your belly and then bounce back up. This can be fun if your penis is pressed against your belly under your clothes and especially if you have an erection. You can push it further by making your erection stick out to form a tent in your pants. I found out the hard way how dangerous this can be, so I don't recommend it. I pushed my erection to stick out too far forward and when I did my front drop I wasn't just imagining my penis being crushed against the trampoline. I ended up with a real penis fracture. How's that for a fucked up masochistic deed?

It wasn't as bad as it could have been, since it was only on the right side, but the pain had me screaming and crying and I went straight to an emergency room. Ever since then my erection has bent slightly to the right and it is about a half-inch shorter over all.