Aki and Sora continue to indulge in their forbidden sexual relationship, unbeknownst to their mother and sister Nami. Even becoming sick or cooking dinner is a pleasurable adventure for the boy given the loving touch of his older sister. Meanwhile, Nami is as determined as ever to catch the eye of her best friend Kana, though the girl continues to have eyes only for her brother, Sora...
After losing their parents, twins Haruka and Sora travel to the countryside to start a new life. The two soon meet new friends in the shrine maiden Akira, wealthy Kazuha and well-endowed Nao, amongst others. As the days go by, Haruka learns more and more about the new ladies in his life, all the while being a patient confidante and good friend, leading him into their hearts, as well as their loins. Meanwhile, Sora can't help but have a recurring memory of her brother kissing her as a child…
Each of these series revolve around some more dramatic topics and adult relationships (often with siblings). If you liked the dramatic nature or adult nature of one series, you'll likely enjoy the other.
If you didn't get enough softcore porn from Aki Sora, you might want to try Yosuga no Sora. Aside from having the word "sora" in their title, both of these animes feature sex and nudity. Does whimpering women having sex with a bishie male lead sound enticing to you? YNS is much more of a proper anime, being 12 episodes long and features some semblance of story, but if it's animated humping you are after look no further.
Both shares the same main topic (love between siblings) and features a good amount of sex and nudity. If you liked Yosuga no Sora but you prefer something similar but more explicit and/or shorter, then Aki Sora: Yume no Naka is for you but, if you liked Aki Sora: Yume no Naka and you prefer something similar but less explicit and with a better developed plot, then you'd like Yosuga no Sora.
Yosuga no Sora is immediately compareable to Aki Sora do to the sexual nature of both shows. Sex runs rampent in both, so if that's your thing, enjoy.
Both animes are about the romance of their forbidden love. Both series have borderline hentai scenes and you can feel their desire to be together. While Aki Sora is focused on the siblings; Yosuga no Sora is focused many girls but, his sister gets her time.
Although they are not related by blood, Keita finds himself the object of his feisty twin-sisters Ako and Riko’s affections. Using extremely creative ways to wake him in the morning, the girls kiss, caress and grope their way into Kei-chan’s bed in the hope of becoming his bride. Forbidden sibling love even spreads to the school classroom, and as the rivalry between Ako and Riko intensifies, will they stop at nothing to win their brother’s unwilling heart? But how far is too far, and can Keita say no to two beautiful young girls throwing themselves at him forever?
While both Kiss X Sis and Aki Sora are borderline hentai Aki Sora is by far the more graphic of the two. It involves rape, nudity, and frequent incest sex scenes with blood relatives. The siblings in Kiss x sis on the other hand are not blood related. I hated Aki Sora, Kiss X Sis OVA was okay, and I loved Kiss X Sis TV, but that's just me, chances are if you like one you will like the other.
Incest, incest, and more incest! Both of these short OVA's are about the forbidden pleasure known to some as "wincest." If you enjoy the theme of "family affairs" you will probably want to check out either of these titles. Aki Sora is a lot more bold in it's depiction of sex, and Kiss x sis is a bit more of a comedy - but if you enjoyed one you might like the other.
On Astraea Hill stand 3 prestigious female-only academies known as St. Miatre, Spica, and LeRim; and though the schools are separate, they share a single campus and dormitory. Nagisa Aoi is a 10th grader who has decided to transfer to St. Miatre's Girls' Academy. Though her transition has been smooth so far, while exploring the campus Aoi inadvertently falls down a hill, sees the beautiful Shimuza, and promptly (not to mention embarrassingly) faints. Nagisa continues to see Shimuza out and about, but soon discovers that she is the "Etoile" -- a well respected girl within all of the schools. With Shizuma taking a liking to the new transfer student Nagisa, secrets of Shizuma's past will unravel over the coming school year.