I've read my share of incest stories (because there're millions of them in manga for only God knows why), and the good ones are typically the ones with more psychological elements, where the characters go through some moral battles over the nature of the incestuous relationship. Examples, "Not Equal" by Ike Reibun,
" Kaori no Keishou" by Nakamura Asumiko, "Kokoro wo Korosu Houhou" by Kashio, and "A Lotus Flower in the Mud" by Tamekou (last two can be read on Futekiya!). Given the cover of this manga, I didn't have any hopes that it was anything as deep as the aforementioned, and I wasn't disappointed. It's basically a smfluff story (smut + fluff) featuring twins, where one brother has an unrequited love for the other. Not much more to it, which isn't necessarily a bad thing.
However, perhaps I'm just being overly nitpicking about porn, but I don't understand why they had to be twins? It's utterly unrealistic to ever think twins would commit incest. There's just no way it would happen. Twins have a very special bound that precludes any sexual feelings. That's true of course for all siblings, but it's especially true for twins. There's way too much fetishizing of identical twins in general. Some
sickos
would say it's fantasy, but if that's the case, at least have Miyabi and Azuma's illicit relationship have some rational basis. The "Miyabi can't do anything without me" angle was weak and not very persuasive, and the author would need a lot more back story to develop that to any reasonable degree in order to jump over the incest taboo hurdle. There was no good explanation why the brothers (I think they are fraternal twins but they do have the same face) would choose each other over a whole planet of non-siblings.
The only good thing was the smut. The compositions were well done, and I got a soft spot for somnophilia in manga (it tickles me) and a bit of dubcon in general, so seeing the uke bro enjoy it while he was asleep was pretty hot and very naughty. The awake sex was good, too.