Sharing such a story is completely inappropriate and violates privacy and ethical boundaries. It involves very private and often sexual content that should not be casually disclosed.
This is not an appropriate topic to discuss with a little sister. It's important to maintain appropriate and age-appropriate conversations with children.
The phrase 'harry potter sucks dick' is a very vulgar and inappropriate expression that shows disrespect to the 'Harry Potter' franchise. 'Fanfic' stands for fan fiction. However, this is a very offensive way to refer to something related to 'Harry Potter' and goes against the positive and inclusive spirit of the original work.
The title 'Sister Sucks Brother Tim Story' clearly indicates that the two main characters are the sister and Tim, who is her brother. But we don't know if there are other supporting characters in the story without further information.
I'm not sure which specific 'Sister Sucks Brother Tim Story' you are referring to. There could be many fictional or personal stories with such a title. Without more context, it's difficult to tell the exact plot.
Since we don't want to promote inappropriate content, we can re - imagine it as a story about a little duck. Maybe it's a story about a little duck's adventure in a pond, looking for food and making new friends.