Probably the most embarrassing thing that's happened to me in my past, would have to be when I was about 14 years old - I was babysitting at my neighbor's house. I had to watch their 7 year old son while they were out of town for the night.
Anyway, since I was just about smack-dab mid puberty, and I hadn't masturbated in about a week, I woke up in the middle of the night with a raging urge to. So I went into the bathroom and began doing so... Everything was fine and dandy until their kid walked in. He had no clue what I was doing, so it was easy to play it off and send him back to bed.
Long story short -- turns out the parents caught him masturbating, and he told them that he learned it from me...

I never talked to them again...

Hehe, so how about you guys?