1: Stacy's Senior Year by Parker If there is a Hall of Fame for erotic writing, then this story is the Babe Ruth, Larry Bird, Bobby Orr, and Johnny Unities of them all.
Very creative, realistic, and all around awesomeness (I know that is not a sentence, but I can't control myself around this story). Stacy gets one humiliation after another, with no end in sight, and the only bad part of this story is that it had to end.
Parker is the man with the exception of his retirement (boo), but this story is his Iliad of erotic writing (without the Greek tragedy).
2: The Smell of Sex by Couture One of Couture's many classics, but I think definitely one of her 3 best. Some interesting plot twists and good character development, in addition to great transformation of the protagonist.
If you love humiliation, this is one of the better stories in the genre.
3: A Mother's Deviant Plan by OldSpice While regretfully never a completed story, this is one of the best set ups that I have read. That and the fact that it is pretty original in its plot and the diversity of the villains involved, make it a great stroke story.
I wish it would continue, since it has the potential to be a great story, but what is there is still enough to always gets my imagination flowing.
4: Black Girls Can't Be Cheerleaders by Phoenix Arrow Just a great overall stroke story, about white girls being dominated by their superior black cheerleader mistresses. Pretty white girls get completely humiliated and degraded, what more could you ask for?
5: Dripping Oil by cowgirl Cowgirl has a great collection of stories even more if you look around the internet, almost all of them focused on women dominating other women, usually with a younger woman dominating the older one.