Let me preface this by saying when I read your description I knew exactly what you were talking about. I had definitely read it before, had in fact read it here at TSR and as per usual, had no idea what the title or who the author was

... sorry. I just want you to know that now we're both frustrated together lol I hate knowing something yet not knowing something. In case I'm wrong though, these are some fics with the roleplay theme that are similar/might be it:
There's the
YKYWT series by Sarah Aless and the
Daddy's Girl series by HotLipedJane and the
Roleplay/Fantasy series by Vampirische Liebe all of which can be found at sinister-attraction. And I believe Sarah Aless's series can be found here at TSR.