This is a manga that's almost good in several ways. But it just doesn't make the cut in any of them.
The story starts simple: a reasonably popular boy seduces a beautiful young teacher and the pretty class rep, making them both eager to have sex with him. Most of this manga tells that simple story from the perspective of each of the three people involved--all of whom see it from a very different angle.
It's an interesting premise (tell the same tale from three different perspectives that make it seem like three very different things are going on)... and it's done okay.
Not wonderfully--mostly because all three of them are kinda jerks, and so I have trouble caring a lot about a plot whose basic premise is three jerks screwing each other--but I can appreciate the concept.
After that, though, the plot keeps going, and just runs itself off the rails. Maybe it got axed, and so the explanations were never printed? That's the only thing I can think of.
So, if the characters had been a bit more likable, the first 3/4 of the manga might have made for an interesting perverted romance.
If the sex had been more thoroughly drawn, it might have made a good hentai manga. (Where the plot standards are lower.)
If the plot had continued and gotten more interesting, maybe it might have made for an interesting psychological drama... at least, that's the direction it seemed like it was headed before it abruptly ended.
As is, however, it's just a hot mess. Best avoided.