Odd that my first comment to your journal will be an embarrassing sex story. And not even embarrassing so much as amusing.
I was going down on my boyfriend (this was 7 years ago or so), and he decided to put his hands in my hair. Which would've been fine, except apparently his spatial relations skill was hampered. He ended up thumbing me in the eye, which caused me to bite down (just a little).
That killed sex for that night, lemme tell ya. "Ow! You okay?" "Yeah - ow! - not too bad, I'm sorry, how're you?"