Hikaru and Shizuku are rival female doctors of the same age and colleagues who, despite their competition, have supported each other through tough times in the medical field. Their long-standing rivalry centers on facial care—specifically skin treatment. Over the years, they've perfected four unique techniques: improving blood flow through direct tongue-to-tongue mucous membrane contact and swallowing saliva, stimulating the nose by pressing the tongue against it and directly spraying saliva into the nostrils, moisturizing and massaging the face using generous amounts of saliva, and deeply cleansing pores by forcefully misting saliva onto the skin. Their exceptional skills have turned this into a fierce battle between two perverts. Features four couples.