HUNTA-277 F** to participate in a "Sex Study Group" organized by slutty girls who just want to take virgins? After going to university, I moved in with my older sister who lives in the city. Then, on the weekends, my sister gathers her friends together and makes a big fuss! All I can hear is erotic talk! To my surprise, all of them are sluts!?

A younger brother who went to university in the city decides to live with his older sister who has moved to Tokyo. However, his older sister is a total slut, and on the weekends she gets into a frenzy of erotic talk with her slutty female friends! When her younger brother is dragged into the group and it's discovered that he's a virgin... they start a sex study session and take his virginity! He doesn't want to let something like this take away his irreplaceable first experience! But the pleasure of his first sex is so great that he can't stop thrusting! In the end, all the sluts beg for his dick and he ejaculates all night long!