Kashidashi Tsuma, Marina no "Netorase" Hōkoku Gaiden 1: Joshikōsei, Marina no Seikan Kaihatsu

Kashidashi Tsuma, Marina no "Netorase" Hōkoku Gaiden 1: Joshikōsei, Marina no Seikan Kaihatsu is a Japanese erotic visual novel in the Marina's Cuckolding Report series. It is the first of two prequel games which chronicle Marina's life and adventures in sex before she met her husband, placing her in the role of the protagonist.

Set during Marina's student days, the game depicts how she transformed from an unassuming schoolgirl who was indifferent towards sex into a woman who learned to love it. In those days, Marina had only had unsatisfying sex with her school boyfriend which she had never achieved an orgasm during. Deciding that she would rather try sleeping with an older man, Marina breaks up with her boyfriend and gets talking to Akatsuki Shindō, an adult working at an investment trust company, who shows Marina what sex is all about.