HND-727 "Sis, let me draw a manga of internal ejaculation sex." The big-breasted sister who became the heroine of an erotic manga, Rinne Tuka

A group of doujin circles preparing to exhibit erotic manga at the next Comiket. However, they are all virgins and have never seen a woman's body... So, they decided to make the I-cup big-breasted older sister of the circle a model for the manga protagonist! Show your tits! Show blowjob! Show in-shot!!! The kind older sister provides her body without hesitation to escalating demands. They even got to draw a depiction of an orgy in-shot while they were at it! This should make it possible to create an ultra-ecchi in-shot work, right??