This is the very first review I'm writing and the reason for that is because of how much space Boku no Yayoi-san took up in my brain.
Story: By NTR standards, this concept is pretty common. The most unique point in the plot was how it ended, on a good note. Well, at least it tried to end on a positive ending, but what came out was something terrible. You see, when you pile up all of what Yayoi did and what kind of human she was from the start, punishment was more than necessary. And of course, this hentai failed at that too. The punishment she took on was more than unsatisfactory. Looking at what she did, she would have to be in a cage 24/7 and I'm not even exaggerating. Not just the whole hentai, but the last two were just done for. It continued to wrap the viewers mind into some place where you just give up.
Art: For something airing in 2016, the animation wasn't smooth, but at a still acceptable level. Although there were moments were even by lowered expectations, the animation felt slow and choppy.
Sound: Nothing new as to hentai standards, but it sometimes dropped lower than that. The only thing ticking me off was that at the doggy scene at episode 3, Yayoi's voice sounded forced. Not the voice actors, the characters voice, like they were deliberately implying the gap the two main guys(which was apparently their dick size)
Characters: Again, standard, if not lower than, hentai standards. The only spectacle of hope I saw that may have split this from the usual NTR was the main characters response to when he found out. But soon, that spectacle of hope was blown away by about 3 scenes and 5 ugly moans.
Enjoyment: The most enjoyed moment of these four episodes was the torturing scenes, and even those were under tolerable levels.
Overall: Most of the time when I watch NTR, I tend to think about it a little, then it just disappears or I try to forget it, but this still lingers about my head every now and then and speaks. It always asks the same: "Why?"
Overall, even for NTR enthusiasts, I don't recommend this.