I've mentioned several times that I have trouble writing scenes that, as you say "go against characters' natures." I've tried to stay more or less true to that in the main FF&S story, although, as you see, I do "cut loose" a bit more in STDH. But some of those STDH scenes were still hard for me to write. I kept having to say to myself, "yes, I know that's not <character name>-ish, but this is an alternate world." LOL
Do note that in the "B" path (which is already finished), Becky sheds a lot of her "reserved" nature with regard to sex. Once Parker crossed the "I love you" boundary, it kind of flipped her attitude. Of course, that's with Parker. It's not like it turned on a Slut Switch.
Anyway, thanks much for the feedback!