I have read (and written) many a scene or book with adult material in it before, but this would have to be the first with step siblings in it. I noticed most of your books do...perhaps it is not really for me, but I didn't really love The Cabin.
It seemed raw, unedited and unpolished to me. I wasn't keen on the repeated step-sister comments, I think it was a bit too much. It felt a bit forced.
The sexy stuff was ok, a little disjointed, a little fast, so quickly it seemed a bit crazy, especially since she had only had one bf before... I know this is geared more to the male readers, and that showed.
Anyway, I could see some great imagery potential in there, it just didn't feel ready yet, maybe with some editing and rewriting?!