I don't have nipple rings, and I can only imagine what it would be like to have them attacked in a fight

Back when I used to fight irl, I had my breasts and nipples attacked frequently, and it was incredibly painful. It was a nipple injury that made me quit fighting irl. With rings, there's the risk of having them torn out and your nipples destroyed in the process. No thanks. If you have them, take them out before the fight...just like earrings, nose rings, belly button rings, even regular finger rings and bracelets.