Firstly, how did you fall down the stairs?!
And my most embarrassing moment would have to be this time I was having sex with a guy for the first time and I was so nervous. It wasn't my first time, but it was his, and I think I was nervous because we went to school together...big mistake. Anyway, I was on top, and I said I was going to bite him. I wanted to bite his neck, but I guess my body couldn't decide if it wanted to bite his lip or kiss him....I ended up pinching my lip in between my teeth and his, and had a fat lip the rest of that weekend...I told my dad my lip was just chapped and swollen...
I always get embarrassed when the lady parts get air trapped too...and I tend to toot a little when getting oral, I've done it once while getting it from behind...I'm with my fiance now, so he's used to it and doesn't care. But the time it happened from behind, the guy said "that really stinks!" Oh lordy!