Quincest

When she met Sarah, she felt more solidly herself than she had felt in years. Do you know about the subgenre of Tegan and Sara fan fiction called quincest? Tegan asked. Sarah raised a provocative eyebrow and leaned forward. Does it involve Tegan and Sarah...fucking? The way she said Sarah made it clear who she meant, and they way she said fucking, what.

Some Tegan and Sara fans wrote "Quincest" fanfiction

The other sequence involves a toxic fan named “Tara,” who once ran a blog writing “Quincest” fanfiction (readers, I apologize if this is the first time you are encountering the idea of twincest fanfiction, and if you are, you should probably not google the term further).