IIRC, it's the one where this girl is close friends with this guy, and so they talk about everything. Then one day, some guy asks her out, and she says yes. The guy silently broods like a loser and continues to listen to her tell him all about everything, then she's all like "hey man, I had sex LOL. It sure hurts having your hymen torn!", then it gets worse because she's being used by the guy, who ends up having her fuck all his friends, and of course she tells him everything without regard to his feelings (bitch, but it's his fault).
Even the guy's friend fucks her before he gets around to telling her how he really feels about her.
Personally, I don't like stories in my hentai, I like happy porn.