"Five Stops" by Radiance (radiance@inforamp.net). I enjoy the thrill of semi-public sex. I have no imminent urge to take off my clothes and run naked down a crowded street, nor do I ever plan to be gang-banged in a striptease joint. But I do enjoy it when my husband comes on to me (or onto me!) and arouses me when there are other people around - or when I do the same to him - or when we have sex in a place where someone else could discover us. I think it's partly the danger of being caught, partly the secret I share with my partner, and partly the combination of innocence and lust that blend together when we do this. It's also just plain fun to tease each other in this way.
In the present story the narrator and Karen have carefully timed the number of seconds between stops near the end of a subway line and have planned a sexual escapade on the nearly empty subway car. The sexual action gets very hot, as the narrator brings Karen to orgasm on the speeding train, while they try to avoid detection. Near the middle of the story, I realized that I could not tell whether the narrator was a man or a woman. I'll let you read the story and decide for yourself. The author does a good job of maintaining the tension that is an important part of this kind of sexual adventure.