"Do you always slip your finger in like this?" He touches me as though tracing the steps of my masturbation... I've never felt pleasure like this! Akari yearns for her teacher. One day, her childhood friend, Yuuta, asks her "Do you masturbate?" in the middle of the classroom. Turning bright red, she denies it, saying, "Of course I don't!" ...But in reality, she does it every night while fantasizing about her teacher... She could never tell anyone about this, and yet, of all people, Yuuta discovers her secret! "Show me how you do it." Blackmailed and unable to resist, things escalate, until...!