When the model goes totally out the window

I love this story from Tom Torero. Sometimes things go bizarrely for reasons mostly outside your control. In this case, he snagged a definite "yes girl" almost by accident. Some of the most confusing times can occur when there are no obstacles. I'm trying to think of a story similar to his, but none have that combination of fast sex with a total stranger met on public transport. A couple times I've slept with friends of women I've been sleeping with, but those situations were more social proof and seeing the moment than game.