I agree with Tiredny about what area of my brain I want to be stimulated by reading the stories here. I don't really want to have to concentrate on a complex plot. But for an erotic story to get out of the gate, the elements of good writing pertain. Believable characters, plausible motivations, and vivid descriptions are important to me.
And accuracy and realism in an historical setting, and consistency in a fantasy setting, is critical. I want to feel immersed in the world of the author. For me that means accuracy of language, customs, manners, clothing, etc. Having said that, I realize that in our little world we're dealing with extreme erotic fantasy. For instance, I'm very aware that the punishment of Mina, in my story, is over the top, and would be unrealistic for the time. I have tried to justify the extremity of the punishment primarily through character (a corrupt, sadistic judge) and setting (a foreign continent where English law may not entirely apply). Whether that works or not is up to the reader to decide.
Of course we all come here to feed our individual demons, and they can have very specific appetites. Personally, I have a thing for non-consensual judicial punishments, involving public nudity, humiliation, whipping, caning, and branding. But one of the great things about this site is the wide range of well written stories. I have wandered outside my own specific interest and read many stories that had an erotic appeal for me that I didn't think would.
I didn't think crucifixion would appeal to me until I read Jedakk's "Serpent's Eye." I don't usually care for sex scenes, but Barbaria wrote a really hot, fully consensual, lesbian scene. One of my least favorite tropes in this genre is the woman who discovers a deep, sexual need for the tortures and abuse she is forced to endure, but Windar's Priya is one of my favorite characters, and she is a cane-slut. I've read erotic fantasy, parody, and even poetry, at all levels of consent and severity, and discovered I have a wider range of interest than I thought.
And while we're on the subject, don't neglect to let the writers know your opinion of their efforts. It's great to get "likes," but personally, what keeps me going as a writer is the comments of readers, whether positive or negative. I don't write "Just for myself." I want my writing to appeal to readers. Sure, you can't please everyone, and ultimately a writer has to write according to his or her own judgement, but still, I think most writers really appreciate feedback.