Help finding a [blkmail][reluc] story about a MILF modeling shoot gone wrong!

I came across a fantastic longer story. I dont remember the genre or the title but the plot has stuck with me ever since.

The story is about a mother, who gets selected (or volunteers) to model for baby products/food. she gets picked up in a black sedan and driven far out of the city to the shoot. during the shoot the photographer has her get naked and says that if she doesnt comply she can walk the many miles back to the city. she agrees (reluctantly) and does all that he asks. he says that he needs to get a picture with a guys dick in her ass and that once he gets the photo the guy will just thrust near her ass. she wants the guy to just get it in in one trust so that its over and the photographer makes a deal with her that if she is able to take the whole thing it, the anal will be over but if not, he gets to fuck her ass until its loosened up for the guy. she obviously cant take it so he proceeds to fuck her asshole. the shoot keeps going and winds up with her pretty much getting gangbanged before the shoot is over. she gets washed up and taken home where she meets her babysitter and her child on her front steps.