Cutting into a guy's hard cock with a sharp knife, or burning it with a cig lighter until the head falls off. Also filleting a penis can be fun, and then you get to take him both ways at once!
Drawback: causes him lots of pain and you have to find a new cock to fuck after.
Bonus: causes him lots of pain and you get to find a new cock to fuck after.
After I cut his cock in half down the middle, I sat on him sideways and fucked him up and ass and pussy at the same time until he passed out from loss of blood. Now I'm looking for a new cock - want to sleep with me tonight baby?
Burning a girl's breasts with a soldering iron to make kewl designs or write words like "slut" and "fist me" across her sexy tit skin. Very permanent, can't even be removed surgically. A good fun way to leave your mark on the world, so to speak.
After I tied her to her bed and raped her for a few hours, I burned "#32" right across her right breast with a soldering iron. She'll never forget me!