Welp, somehow I ended up spending a lot less time on anime than I thought. The only anime I'm currently avidly watching is Boku no Hero Academia.
Last anime I've finished was Doreiku. I used to read the manga 3 years ago, so my interest peeked when I found out about the anime. But I guess my tastes might have changed over the years, because I didn't enjoy it as much as I thought I would.
(It's not about BDSM, just to be clear)
In short, it's about a device that when worn in the mouth, will either make you a master or a slave, depending on whether you win or lose the challenge. The story talks about of a handful of characters that have been succumbed to that device. The show was entertaining all in all, and the ending was satisfying to me, I'll give it that.
It seems from the amount of comments I've read that people hate this only because of the NTR that happens in the first half of the show. Like what did they expect? It's a show about enslaving people.