I find that there are a lot of fandoms that I enjoy, but only so many that I want to write in, porn-wise. My criteria are more or less these:
The fandom has to present a lot of opportunity for turning situations porny. Any show where there’s mad science, magic, or characters from other worlds with totally different cultures is good.
If it’s TV, it has to be animated. I feel weird writing about characters who are physically portrayed by real actors.
If the characters are young, they need to be precocious in some way.
I think this explains why I write lots of stories about fandoms like The Loud House and Phineas and Ferb but not, say, Milo Murphy’s law or Person of Interest.
How about y’all?