Kurokiya-san Wants to Lead Him Around by the Nose Volume 3

So... just how far have the two of you gone? Searching for a place to continue the study sessions, the two end up alone in Ruu's room! Just when it seems everything is going too well, a new figure appears to block the way... Ruu's mom? A mother's worry for her teenage daughter and visions of the ravages of teenage lust, drive the Gyaru Mama to shocking actions!