DSOD-002 - The cold younger sister whispers, 'If this gets out, our lives are over,' and drives me insane.

Toru visits his girlfriend Mizuki's house and meets her sister, Sarina. Though she acts cool and distant, she seduces him with dirty talk and erotic tricks when Mizuki isn't looking. She pushes him to the edge with handjobs and blowjobs, eventually escalating to relentless sex that breaks his last shred of reason.