If you liked the Nozoki Ana manga, the Anime-Planet community thinks you'd like:
On the surface, Nana Chigusa appears to be a typical honor student, loved by the student council and her peers, and surrounded by admirers and friends. But deep down, even good girls need a way to blow off a little steam and de-stress, and for Nana, that means secretive, intense S&M sessions with Kaoru, a well-known pervert and her childhood friend. What experiences and pleasures await this unlikely pair?
Two explicit titles that revolve around mature fetishes, with elements of S&M and/or control/power over another (Nana to Kaoru more so). If you liked one, try out the other.
Both series are about sexual secret that boy and girl hold and even people Who interrupt in their live are similar in "Nozoki Ana" and "Nana to Kaoru" if you like this manga then most probably you will like the second one.
They both cut very deeply in the ecchi/mature theme genre but they are well made or better said well written. It's been so much fun reading them they cover a romance-lovestory in a kind of "hentai" way but still got coverd the story... just check it out and you know it certainly isn't something for everyone but I'm sure there are people out there which will like a good laughter and a pretty unique story handling.
Check them out they are worthwhile.
When Akiyama booked a vacation for him and his girlfriend at Koibana Onsen – a place known for helping unite couples both mentally and physically – he had no idea that they’d break up days before the trip. After arriving solo and meeting the onsen’s three sisters, not to mention getting the ‘special treatment’ from each of them to help him feel at home, Akiyama decides to stay and work part time. Now, with one of the sisters as his newfound girlfriend, Akiyama will work together with the trio to help make each couple’s visit a pleasurable and exciting success, in addition to losing his virginity and discovering the ultimate pleasure himself…
Every day after school, the quiet and introverted student Kurosawa goes into the empty girls bathroom and "relieves himself". Besides this extremely odd ritual, Kurosawa also has a thirst for justice and a judgmental attitude towards his classmates. Upon seeing the bullying of an awkward girl in his class by two of the "popular" girls, he decides to bring justice to the bullies the only way he knows how. His plan for revenge goes "just as planned" until met by an unsuspected accomplice.
Nozoki Ana and Onani Master Kurosawa are similar in the aspect that they both have a serious plot based around the subject of sex and masturbation respectively. Both play with the aspects of human emotion, interaction and serious character development. In both there are characters who aren't quite what they seem to be. If you like one of these, I can almost garuntee that you will like the other.
Hideo Aiba is anything but popular. Not only is he a high school virgin, he's also a part of the "Roman Club" – a group of guys with bizarre fetishes. But Hideo's unusual school life is changed forever when the mysterious Kurumi transfers into his class, joining the Roman Cub soon thereafter. Together, the two begin a strained and pleasurable relationship where Kurumi controls Hideo's very desires... and actions.