I don't know if this counts but:

When I was a HS Freshmen I used to get a major hard-on every day just as first class was ending. I have no idea why. It would just always pop up. Most of the time it would be down my pants leg which is worst case. Stand up and the the stress on my penis was huge. I'd have to grab it and pull it up.

Every day it was a struggle to find a way to hide my "grab and pull."

One day it was poking straight out. I walked out into the hall holding my books in front. The hall was totally packed with people. A fantastic looking babe was smashed into me by the crowed. My books pushed aside and my penis hit her square in her crotch.

She looks up with a pissed off look - probably thinking I grabbed her pussy. Then she looks down at my hard-on. She seemed very surprised. The crowed pushed us apart. I could see her stuned look as she was pushed down the hall.

I'm sure she got a total "feal" of my penis.

It happened so fast I didn't have time to be embarrased.