I'll start by saying the story is not "Pippa" or "Sister Pippa"
As many are, I'm looking for a story. However, the search terms I need to use are either so vague they pull nearly all the stories, or too detailed that I miss it.
Here is what I remember:
There is a brother and a sister. The brother gets injured, and breaks, I THINK, both of his arms. It but it might just be one of his arms, I can't remember exactly. Because of the injury, he can't masturbate. Somehow, he is able to convince his sister to help him out with this problem. She helps him while he's in the shower, and it starts with just simple masturbation. Originally, shes dressed, then its down to her bathing suit. Then she starts wearing less and less clothing. Then she starts doing this topless. As time passes, she gets more and more turned on by what she is doing.
The brother is trying to get her to shower completely naked with him, obviously enjoying the attention. It all comes to a head one day, when the sister is speaking with her friends about how much they like her brother.
She finally has had enough, and the next time they shower, she does it completely naked.
They eventually make love, and its all good.
It was one of the best, hottest, longest, and a serious personal favorite. I read it once years ago, but lost the bookmark when my house got struck by lightning and took out my computers and my backups.
If anyone knows what that story was, I'd be forever in your debt. Thank you for the time to read this. Good Luck.