yes, another person looking for a story!

[Prizmatic]

Hi guys, I read this story once or twice but didn't bookmark it, and I haven't had any luck searching it. It was an incest story involving a guy named Scott and his older sister Trish. It seemed like Trish was exercising some kind of mind control over him because he kept having these vivid fantasies about her and then she'd always smile. She was in college and I think they were from Toronto. I read part 2 and couldn't find part 1. If anybody can remember the title or author I'd really appreciate it.