I think Minor1 was the first one to fall for me, and I had tried so hard in the beginning to avoid it. I did come to realize that in the end, it’d have to come in anyways due to the nature of the universe that I’m creating and the realism I’m trying to embed within in. Kids will experiment with it, its not like they will avoid all sexual thoughts until they turn 18 or even 14, especially as it’s in our media all over the place. I had shifted the line to puberty, but even the current story I’m working (Jefferey) has challenged me there, and the line’s shifting, again, due to the setting (which, I had first avoided with a four-year time jump that I balked at when I started working the revision). I even know the scene that started to chip at the minor1/minor2 distinction in Alaska Trekkers, and I was trapped, because I needed the main characters at specific ages (as they couldn’t be too old), which meant the younger sister couldn’t really get older (biology).
WS isn’t a squeamish one for me, so there’s really’s never been a line on that for me. I’ll try to make sure I don’t overdo it within a story, but I like how it can basically show a gain of confidence and trust in a relationship, to lose the inhibition and that sort.
Nec was one that I had avoided too, though I finally decided to embrace it as a challenge for my last Halloween fic, in the process, MBP decided to tag along.
Hard scat is definitely one I still try to avoid, it still squeaks me out. I will list it, though, as there are situations where I’ll describe my characters taking a dump and it can become a bit pervasive at times (all the reasons, whether its illness at a rather inconvenient time, or somebody’s scared, or to just plain embarrass my character – though I do have one who’ll do it as pranks). So for my stories, the [scat] tag is typically CYA. (However, that last halloween story challenged me a bit there, brought it closer to true scat.)
Xeno is about the only one that can’t enter, simply due to the construct of the universe I’m writing. (ie, there are no plans for aliens)
So, of the list, the one I seem to most actively avoid is …. SFW
And, thanks for that vote of confidence @CloverReef.