It was a story about a widow with her real son (not a shota son, but i think he was definitely above 16), and how she basically grooms him to be her perfect lover. It was a story i found in storiesonline i think, and it also had a couple of chapters: A dozen, i think? A lot of snu snu, basically a stroke story. Found it: My mother's lover
Well, maybe what I read is something different than what you mentioned. Edit: It's different than what I read. Somehow the site got blocked in ny region... Interesting..
An aside, just go to asstr.org for anything you want. Or for a more organized (categorized) selection from that site, one of the collections: asstr.org(~Kristen/ then down to "Kristen's Category Archives".
illicit relationship has a good incest story, i like the romance between MC his mom and aunt. Pretty wholesome for something so blasphemous