A short love comedy using S&M for lure readers, but without explicit sex and the plot is developed above the average for these genre. The popularity convinced the producers to expand it to a longer version. Let's see why.
Up today in 32 chapters no genitalia as being showed, no sexual intercourse. But is soo ecchi, with fanservice and sublte sexualy charged, that is like the difference bettwen a "raw" nude and "sugestive" lingerie. The ununsual Soft-porn approach is a positive selling point that counter the Hard-core reputation of S&M.
Not the main attraction, but a very important part of the manga. They seems to really care about each other, but their new link is also an obstacle for a deeper relationship.
What come next?
Is like a soft drug, the characters want to experience new things and the readers want to see how things slowly scalate to a new levels of ecchiness.
What they are thinking?
In my opinion, the best part is how the autor try to make things beliable, in place of use simplistic or bizarre explanations/excuses like family problems, experiments, demons, etc... emotions and feelings are explored. Strees, inferiority complex, trust, forbiden, guiltness, humilliation... The "trainer" play mind games, but is sabotaged by love to the "trained". Amusing as cute.
Neither too shallow nor too deep. The act is a balance, like a beatiful acrobat walking in a rope and being teased by a clown. I think that the characters/plot are delivering more than it was originally planned, so Im happy that they extended the manga. But how long the autor can keep the act going on, or if can make a more satisfactory ending that I dont know. For now, I want to see "what come next?"