Ooh, this is such a neat alternate explanation of what might have/could have happened. You did such a great job with Snape's "victim's guilt" and feeling dirty and ashamed. I love that he (and Remus) found an even better means of retribution than simply turning them in, though. Perhaps Remus should have been sorted Slytherin!
Snape's bonding with the werewolf in the aftermath of his trauma is an unusual and fantastic sort of h/c. "He was better than you!" -- LMAO! So great that Remus still wants him post-transformation. LOVE the way the meaning of the collar shifts.
Also, a Snape who's able to be the bottom and still be Snape is a HUGE plus in my book. Nice.
And oh, I'd bet my right arm I know who you are, "Mystery Author!"