Mature girl / Shishunki Shoujo: Kari Kari

The hentai protagonist Koizumi-kun is crazy about his classmate Rin-chan, but with his perverted personality and habits, he doesn't even hope for reciprocity. However, Rin herself has been in love with our hero for a long time, and shyness doesn't give her the strength to confess to her beloved. By a strange twist of fate, Koizumi saves Kumi, Rin's best friend, from rape. And she, in gratitude, gives him passionate sex...