[Request] Looking for an old story...

I remember there being a story I read, I'm pretty sure it was brother/sister. They were fighting and she kept on going for his balls. What made it stand out to me, was that he was getting *really* angry about it, way more than you'd usually expect for these stories. But she went for it again and again, I think he might've been hospitalized? I think there was a time jump too.