DVAJ-371 [Uncensored Leaked] A life of incest with my sister who lets me insert it up to 3cm, Aoi Kururugi

An older brother notices his younger sister Aoi's suspicious behavior. When he confronts her, she reveals that she's been practicing putting on a condom with his penis. Since then, he's been helping Aoi practice putting on a condom, but... leaving him erect is too painful, so he asks Aoi for help with ejaculation. Unable to endure just a handjob, he also gives her a blowjob and a pussyjob... Finally, the two of them reach the brink of penetration, and they decide on a rule that "if the tip is only 3cm deep, it doesn't count as sex," and they start having repeated glans sex. Before long, just inserting the head of the penis isn't enough, and they both want to penetrate each other's vaginas deep.