Yuna grows increasingly frustrated as her husband repeatedly loses his erection. During another sleepless night, she discovers that her live-in son-in-law Ryuichi is also neglected by her daughter and masturbates alone every night. Stunned by his exceptionally thick cock, Yuna can no longer resist her desire. Under the excuse of “taking care of him,” she services his cock day and night, becomes addicted to its pleasure, and devours him with abandon while he unloads his overflowing sex drive on his insatiable mother-in-law.