Even when their son is right nearby, Rin, a wife, repeatedly engages in lewd acts with her husband. It's enough to make the teenage son get an erection. As this happens over and over again, the son begins to think of his mother as a "woman." Realizing this, the sexually-strong mother starts to provoke her son, and the two of them end up... Since then, the son has been craving his mother's body even when his father is at home, and they go wild every night...