I have a sexy European (English) Internet Lover. This is moreso badmasturbation for him.
One night we were "trying something new" in the sense of the act we were Role Playing out... Bumplay, and he's very insecure that he likes bumplay...
I for one only really get off with him enjoying the bumplay, I myself am not a huge fan of it. We were getting into what we were typing pretty well, and he suddenly had to leave. I later find out in mid orgasm he broke a glass all over his keyboard (I'm pretty sure he scratched up knuckles, or something).
Like I said, not too bad, he broke a glass and made a mess in his room, and I didn't get off, but whatever.
The only other "bad" experiences I've had would be almost getting caught. I'm sure my mom knew, but I was under the sheets... I just wouldn't come out of the sheets, because she didn't need to see me bottomless. This has happened more than once, I'm sure she's out to get me.