As far as smut goes, this is the cream of the c***.
The fetishes it deals with are voyeurism/exhibitionism and cheating/cuckoldry, with a base of blackmail. I love the way the nipples are drawn, though the nudity in general is very erotic. If it's not clear from the title and synopsis, the premise of the story involves a peephole--Kido's neighbor Emiru blackmails him into agreeing to a peeping schedule where they will be allowed to peep on each other on alternating days; she wants to see him having sex with other girls. This continues for about two years, during which Kido has two girlfriends and has several encounters with quite a few other girls wanting to push him into having meaningless sex. Several people find out about the peephole and react in various ways, and there are also a few instances of Emiru almost being raped as well as several instances of her molesting other women. At first, Kido sees Emiru as simply a heartless pervert, but over time he starts recognizing the more vulnerable and caring sides of her personality. There's a recurring idea of trying to fuck your relationship problems away and how that ultimately doesn't work, and how relationships need to be built on openness and honesty.
Obviously, all manga have problems and this one is no exception. The biggest problem was how the ending seemed to drag on as it kept including flashbacks and attempts to tie everything together. And related to that, at times the narration and descriptions of emotions came across a bit heavy-handed, like they were over-explained or something. And then, some of the plotlines and situations they got into started feeling a bit repetitive. But these negative aspects are overshadowed by the general enjoyability and many of positive aspects to the manga. To list a few: it stands apart from the crowd and feels like it tells a unique and original story; it has appealing artwork and lovable characters; each chapter leaves me wanting to read what happens next; it's still enjoyable during the second or third readthroughs; and, most importantly for an erotica, the sex scenes are well put together.