I debated putting this on my "bdsm slave fantasy" shelf. It's definitely not bdsm. And it's not really slave fic, either; but at the same time, it is. It's sort of consensual non-con. I don't know. Hard to classify. Even though it's not really bdsm slave fic, it activated the same parts of my brain so I enjoyed it in the same way I do those kinds of books. So if you like that kind of thing, you'll probably like this even though that's not really what this is. If that makes any sense at all.
Basically this is a story set on another planet where the aliens keep humans as pets. So the humans don't really have a choice (hence the non-con), and their owners have sex with them, but the humans are all happy and love it so in that sense it is consensual.
It also has an m-preg element, where the aliens "impregnate" their pets with eggs that the humans carry in their ass for four weeks before they "drop" the egg. Is that m-preg? I mean, they're not really pregnant. They're just carrying eggs up their ass.
But anyhoo. I only say the above to give people something of an idea of what they'll be getting into.
This was a very enjoyable book, just because it was so original and fascinating. Had this been a regular old contemporary romance I would have HATED it because the romance elements are incredibly cheesy. This would have ended up on my rainbows and lollipops shelf. And probably also my abandoned shelf. But since the setting and the story and all of that were so interesting, it was easy to ignore all the "I'm so happy and horny and in love" stuff.