Read this story online years ago, but cant find it anymore.
It was something like "The worst day of my life" and is about a 16 year old going to a waterpark and forgetting her swimsuit. Think her name was Erica.
Her friend then convinces her to swim topless and pretend to be younger because she has almost no boobs.
She does it, but gets exposed and loses her panties as well.
Other friends also embarras her and there was a second chapter that takes place at school.