Where Lurks the Edge of Dark Erotica?

Public Domain Art - John Henry Fuseli - The Nightmare

Where lurks...? Yep, I went for the creepy verb effect with that title but really what I'm asking is, what the hell is Dark Erotica? 

I started wondering about this before I wrote my latest book, Take Me, Break Me because I wanted to dip my toes into it, and now after publication I'm seeing even more clearly that it's not that clearly defined. You see Wikipedia also calls it Erotic Horror and does a very bare bones definition of, 
"a term applied to works of horror fiction in which sensual or sexual imagery (or even descriptions of the physical act of sexual intercourse) are blended with horrific overtones or story elements."

Yet on Goodreads the Dark Erotica group defines it as 
"the more aggressive form of Erotica. This would include storylines with rough sex, forced seduction, rape, kidnapping, BDSM, and those who enjoy alternative lifestyles to the extreme, multiple partners that may or may not involve same sex interaction"


But I like another definition, a far simpler one - dark erotica is a story with fear plus lust. Because in a way this covers both of the above. Fear is so personal. Something that scares you, another person will brush off as nothing much at all. 

Horror is surely a more horrible form of fear? True. Yet some of the most well known books of this sort of erotic story, such as Captive in the Dark, may cause mild fear or an unsettling feeling but aren't going to cause that true hide-under-the-bed horror that you get in a horror movie or a classic story like The Monkey's Paw (which is pure horror, not erotic horror).

So to me, erotic horror is different from Dark Erotica, or it's a small sub-section of it. And so my romance story, Take Me, Break Me, which I deliberately wrote to drift about on the edge of the darkly erotic realm, has some readers going...

"Wow. I can't express all the emotions I got from this read and I'm pretty jaded when it comes to deep dark erotic romance." Michele Harvey, Goodreads review

And others are going, no, never, that's not dark erotica at all.
Funny how we like to scare ourselves though, isn't it? Not that I read dark erotica to be scared exactly. It's more of a thrill, I think. Now I'm wondering if I got that definition right after all. 
                                                 Lust + Thrill plus or minus Fear?
I think I need a maths degree to work this out.

PS Erotica is the wrong term anyway for a fleshed-out erotic romance IMO but that's another definition for another day.


Here's a great review blog I found today for dark erotic books: Jessy's Book Club 

Adding some more thoughts.
Having done some more thinking...really, that definition should say that the lust and the fear have to be there at the same time. I could make a horror story where the sex and the horror are in different chapters and that is not dark erotica. 

I'm also wondering if dubious consent or non-consensual scenes of sex need to be in the story. I think they do. Because although the wikipedia definition may not say it, but I feel it's pussy-footing around the true meaning. A story where the son of Satan, or a succubus, rapes a woman is still non-consent despite the non-human attacker. Am I right there?