Living alone with her son after losing her husband, Eri finds herself caught one day when her son discovers her masturbating. Overpowered and pinned down, she initially resists, but overwhelmed by pent-up desire, she eventually gives in. That dirty feeling—ah, her backdoor feels so incredibly good, she can't stop anymore. She craves her son's masturbation, begging him to thrust into her mother's anus. Her secret masochistic side exposed, she's tormented repeatedly with electric vibrators, intense anal play, and nipple torture, brought to the edge of orgasm over and over. Lost in the depths of this pleasure, her days melt into a haze of indulgence.