Mio Oshima, overly loved by her girlfriend's younger sister, secretly tries to conceive a child. (HND-265)

Your girlfriend's younger sister, Mio Oshima, loves you so much! You've been seduced by her and are secretly having sex with her every day behind your girlfriend's back. Seeing that sweet smile on her face makes you feel so guilty towards your girlfriend. Secretly going crazy and fucking her is so amazing!