In my early twenties this guy and I flirted for nearly a year before we finally decided to take it to bed. He had a nob that porn dreams are made of but my feet and legs kept catching on something in his bed and scratching me... hard. I shifted positions, but nothing helped. Finally, I interrupt what we're doing to look down and see that it's his jagged toe nails. And they aren't scratching me, they're cutting into me. I actually have blood running out of at least six wounds onto his sheets. My boner deflates in an instant. He's apologizing profusely and I catch side of his bloody nails and just want to puke in his face. Couldn't get out of there fast enough.
Now that I've finished relating my tale, I think I was more horrified than disappointed.