Some things I was able to put my finger on after looking at a bunch of the images in the feed:
It doesn't do skin well, treating it more like a smooth plastic than a surface with pores, wrinkles, and fine hairs.
It doesn't understand lighting, so shadows don't agree with highlights or even each other.
It doesn't understand anatomy. A lot of the images were fine in this regard but others had misplaced muscles, bones, and impossible limb positioning/truncation.
It has no idea how to draw vaginas. Nipples are also not well understood, though it does better on average with those. They still look more like a plastic than skin, but most of them were passable at least, while I didn't see a single vagina that looked even close to right.
Yeah, a lot of the vaginas on that site look like hentai vaginas. I can understand it more with AIs since vaginas have a ton of variance to them, so trying to make an "average" vagina will end up not looking like any actual one.
But the artists that draw them like that just disappoint me (though with the caveat that I have no reason to believe I'd do any better if I were to draw that). There's a ton of inspiration out there and many do an amazing job with the rest of the body, why do they make one of the important parts (for porn) look like an afterthought?
Though the anime style ones aren't as bad as some others where the AI seems like it's trying to average boy and girl parts lol.
Using a term casually rather than medically won't affect the quality of AI porn. Though maybe ensuring it knows the difference between a labia, clit, urethra, vagina, and asshole will produce better results.
You can do multiple subjects but you have to be more creative than just throwing a prompt into a generator. You have to be willing to do it in multiple steps with in painting.