Teenage Tooru was intensely drawn to his mother Erika's sensuality. Peeping at Erika through a bathroom window while she bathed, he would fantasize as his cock grew hard. His desires intensified each day until mere fantasies could no longer satisfy him. One day, he played a prank on sleeping Erika. Unbeknownst to him, his actions deeply excited her. For Erika, who had recently endured a sexless marriage, her son's advances became a thrilling new stimulus, gradually relieving her pent-up sexual frustration.