As a girl, I don't have any stories of my own. However, my guy's best friend went camping with a girl who gave him a bj and and threw up on him and the sleeping bags. They were way out in the mountains.

I've definitely had my share of gagging, but I'm not sure how someone gets to the "I'm truly about to puke on this guy's penis" without realizing it and stopping. Drunk, maybe... But sober?!?