"Have you ever been to a backdoor sexual entertainment place?" Because of a brief comment made by his kouhai, the pleasure-loving Saeki teases his own butt. However, the battery he thrust inside got stuck!? He rushed to the hospital and was treated by a gastroenterologist, Kirishima-sensei. When he consulted him about the location of his prostate, he used his finger and explained it hands on which felt crazy good ? "Would you put your dick inside?" The cool technician doctor x the sex loving straight man's sex love story that started with treatment!