First, a quick summary: each chapter involves Shiori-sensei wearing a different type of cosplay and having sex with the other teacher, Yazawa-sensei. It's pretty good at first, it's a "happy sex with love" type of story. Unfortunately, it gets worse the longer it goes.
First of all, in the initial chapters there's actually some story and romance in addition to the sex. That gradually fades away as time goes on, and the chapters turn into getting Shiori-sensei into cosplay and then sex as fast as possible. Shiori-sensei also gets more tsundere as time goes on, it's not NonCon per se, but she gets more and more tsundere during sex. It ends up feeling like their relationship actually gets worse as time goes on.
Also, the sex is all the same, simple vanilla sex. No oral, no anal. I have no problem with this by the way, I was still sticking with the series even when it became just hentai.
The problem is that part way through volume two there starts to be, groan, different girls introduced who aren't even fucking loli.
OK, if you want to write a harem series with one loli, that's fine. I won't read it, but whatever.
But you can't start a series as a "happy couple having lolicon sex" series and have it turn into a "harem sex friend no romance" series part way through, that makes no sense.
1). Anyone who wanted to read a series like that wouldn't have started the initial series, and 2). who the hell bait and switches their readers like that, what the fuck?!
To summarize:
1). The "cute scenarios" described by the other reviewer disappear by volume 2.
2). Shiori-sensei becomes tsundere to the boarder of NonCon.
3). Their relationship degenerates from happy romance at the start to more like sex friends.
4). More girls introduced starting late in volume 2 who aren't loli.
Well, this review is a bit long for a hentai, but I thought an update should be posted to steer people away. The series was quite good back when the initial reviewer reviewed it, it's a shame the mangaka chose to take it in the direction he did.