Musuko no Tomodachi ni Okasarete / Son's friend

 Yoko-san is happy in her marriage and lives a calm life with her husband Masahiko and son Kazushi. However, recently she has been bothered by the complete lack of sex in her family life for a long time. Every day, her son's friend Ryoto-kun comes to her house - he is a well-mannered, handsome, and incredibly sexy guy...