I feel the need to comment here. In two stories that I've posted the female characters ended up doing things orally that didn't feel quite right. I know it sounds a little on the delusional side, but I grew fond of these women as I wrote the stories and felt like I betrayed them somehow. Perhaps these were examples of "less is more", sexually speaking.
LostLady, I find, in those cases, that the characters are warning me, the author, that the story is venturing into dangerous territory. In short, the characters know how they'd act. If they protest, it's probably because you're making them act out of character, and readers will likely respond.
Whenever I hit that stage, I backtrack, put the story aside for a short time, and then reexamine it to see where the story when off track. I usually come to a better understanding of the character and end up with a better story.
As the story progresses you get the know the characters, and when one (or more) of them does something that's completely unexpected and out of line with what has gone before it really does kill what could have been, or up to that point, was a really good story.
By the way, Grant, if that case, I'd contact the author, as a courtesy, and tell them that they need to 'flesh out' the character change more, since the change 'seems unjustified'. It doesn't take much to add foreshadowing to a character change, but if they write stories a chapter-at-a-time, it can be difficult to change after the fact.