Unsatisfied with her husband, Yuki Yoshizawa has been masturbating more often. Then she catches her live-in son-in-law Atsushi secretly doing the same at night and becomes obsessed with his enormous cock. Claiming she will relieve him because her daughter refuses to put out, Yuki offers to handle his sexual needs herself. From morning to night, she seizes every opportunity to suck his huge cock and drain him again and again. After being made to cum until he can think of nothing but sex, Atsushi faces an irresistible temptation.