I'm certain I read it on SOL years ago, but can't find it using these key words in an advanced search.
My memory is foggy on details, but a HS cheerleader goes on a date with a nerdy type to win a bet - maybe something about getting him to cum in his boxers without touching him. He ends up giving her a very powerful, sensuous massage when she gets muscle cramps from her cheerleading practice. massage leads to more dates and eventually they have sex where she has mind-blowing orgasms. Seems he was trained by his three older sisters in the art of massage and also sex. IIRC, all activity takes place in his van.
(It's possible I've combined a couple of stories in my memory, but it's definitely not ElSol's El Sobador.)