Hey, did you have sex in the bathroom of a Motorhead/Megadeth concert in Chicago? Do you have a red mohawk and black pentagram gauges? Congrats, you're a father.
I was grinding on you in the pit, then we went to the bathroom, and got fucked up. You had a nice cock and I was wasted so I let [you] raw dog it in the stall. You were really good and you had to gag me so I would make too much noise.
But with raw dogging comes consequences: in this case, a little bundle of joy you may or may not be interested in raising. The Craigslist poster is actually pretty mellow about it. "Contact me if you want to be part of your child's life," she writes.
Best of luck to all parties involved.