Occasionally, childhood friends enter into a relationship seemingly out of convenience, as is the case in Namahame Osananajimix. Tomoki maintains a strange routine of groping the breasts of his childhood friend, Chinatsu, who in turn slugs him for this assault. One day, after their usual exchange, Chinatsu confesses to Tomoki that she is the only one of her friends who has yet to have sex, and Tomoki is the only person she trusts enough to take her virginity. After some initial trepidation, the two throw themselves into a sexual frenzy in order to help Chinatsu become as experienced as her friends. While it does not excel in any single area, Namahame Osananajimix earns its spot at number ten by providing a great overview of what childhood friend hentai is, while being overall enjoyable. That being said, Tomoki's breast groping scene detracts from the overall theme of innocence that is the cornerstone of the childhood friend genre.

A childhood friendship is as innocent a connection as two people can share, and in Re: Hatsukoi, Kirika Toosaki finds out how far someone could go to preserve the sanctity of this bond. Kirika is a teenage delinquent who has modeled herself around the image of her senpai, an ex-delinquent who is now her straight-edged teacher. One day, after the two have a confrontation about Kirika's clothes at school, she shows up at her senpai's house, where he is forced to give her shelter from the pouring rain. A nearly naked Kirika entices her senpai into having sex, during which, it is revealed that he maintained his virginity because his love for Kirika prevented him from dating other women.

Re: Hatsukoi's narrative manages to capture the effect that a difference in age makes in a relationship, as Kirika is revealed to be a petulant child, unaware of her senpai patiently waiting for her to mature into a woman. As is the case with many childhood friendships, these two were forced to separate, but luckily, their love ultimately brought them back together.

The nature of growing into adulthood is such that people feel a certain need to move on from the places and people of their childhood. In Koakuma x Osananajimi, Haru is planning to move away from his hometown, but this news comes as a surprise to his childhood friend Miya, who has grown accustomed to having Haru watch over her. To avoid living without Haru, Miya springs into action and begins sucking Haru's soul out through his cock. This is all it takes for Haru to give himself over to Miya's sexual desires, after which he vows to remain by Miya's side.

This title is emblematic of this genre as a whole as it manages to encapsulate the idea of two young friends using sex to secure their uncertain futures. As satisfying as a manga that is as well-executed as Koakuma x Osananajimi is, sometimes we like to read manga that subverts the genre's expectations.

Osananajimi manga largely follows the same plot points, which makes a manga like Osananajimi no Gin no Hane a rare treat for anyone looking for some variety. Shouta Fumizuki dreams of his friend Akane, who disappeared from his life five years ago after promising that she would see him again one day. After waking from one such dream, Shouta meets a girl who reveals herself to be his missing friend, who has now returned as a semen-sucking tengu. She proceeds to harvest Shouta's seed, only to find that it has a powerfully intoxicating effect which compels her to stay near Shouta. As unusual of a premise as this is for an osananajimi manga, Osananajimi no Gin no Hane manages to draw in the reader with tantalizing illustrations but holds our attention by selling the narrative that the love between childhood friends is strong enough to make Akane give up her semen stealing ways. The only aspect of this manga that may strike a sour note with readers is Shouta's initial objection to being raped.

Perhaps it is part of the fantasy aspect of manga, but men in osananajimi stories are always reluctant to have sex, and in Nozomi Wish, this is a real problem. Nozomi is sexually frustrated because her childhood friend Keiichi refuses to fuck her, and she lets everyone know it. Because of this, Keiichi has avoided the topic until Nozomi's constant badgering leads him to promise to have sex with her but only if she can jerk him off for an entire week without letting anyone know about it. By the end of the week, Keiichi is barely able to restrain himself long enough to take Nozomi home to fulfill his promise. Despite her deep, carnal desires, Kisaragi Gunma manages to portray an earnest innocence in Nozomi through his artwork, which makes the manga all the more meaningful. Nozomi's gentle looks, however, do not prevent her sensuality from charming Keiichi or the reader for that matter.

The childhood friend genre in hentai is unique in that women are far more likely to initiate the sexual aspect of a relationship than their male counterparts. In Osananajimi no Kinpatsu Gal Bitch ni Gyaku Rape de Doutei o Ubawareta Otoko, this results in Sumi urging her childhood friend, Sadaya, to fuck her. When he refuses, she forces herself on him until he desperately asks her why she is doing this to him. That's when Sumi explains to Sadaya that, when he previously rejected her, it caused her to change her entire personality in the hopes that he would change his mind. Upon hearing this, Sadaya realizes how short-sighted he has been and ends up giving Sumi's pussy a thrashing like none it's ever had before.

Sahara Gensei's characters in this manga walk a tight line between being innocent young lovers and sensual beasts of passion, in a way which makes the reality they inhabit seem more true to life than it has any right to be. While the key to this manga lies in the characters being real and emotional with each other, other manga are less subtle.

As a form of escapist art, it can be said that manga is at its best when it portrays high fantasy plots like the one in Aibuka! When Sky Ito finds that his idol research club is being canceled, he enlists the help of his childhood friend Yuzu Onodera to save it. To prepare Yuzu for her idol debut at the school festival, Sky takes her virginity, secretly makes her a gravure model, forces her into a lesbian orgy, and throws in a few singing lessons here. By the end of this six-volume manga, Sky has convinced the president of every school club to join Yuzu on stage so that they will be unable to cancel the club.

While not exclusively an osananajimi manga, Aibuka! scores extra points for creating an entire six volumes of erotic encounters while having a childhood friendship in the middle of it all. Of course, this takes a lot of liberties with what could reasonably happen in a school, and not everyone appreciates taking the reality out of this kind of manga.

The reality of sex, be it between childhood friends or otherwise, is that it can be impossibly awkward, as the characters of Osananajimi found out first hand. Tomoki Sasaki has just been caught jerking off using the panties of Mirei Oda's mother. Tomoki explains that he only did this because he believed that the panties belonged to Mirei, a sentiment which she does not appreciate. He begs for his childhood friend to take his virginity—a proposition which she does not approve of but eventually gives in to— and this leads these two childhood friends to explore their true feelings for each other while having some awful yet endearing sex.

The characters of Osananajimi feel all-too-real, stumbling through their first sexual encounter the same way most of us did. The graphical style of this manga, coupled with its fully realized characters, definitely make for one of the most interesting reads on this list.