I've heard of something called 'wound sex' where you basically make a flesh wound in your partner and fuck it, but I've no idea how common that is. The only people I've ever heard talk about it were the shock-value types who are into--or at least pretend they're into and talk about--really WTF things just to shock people, so I wouldn't think there are too terribly many people into it. But since there are guys with castration fetishes, it wouldn't surprise me if there were at least a few people who like it.
Either way, I'm too scared to look it up.