Manga Sadou: Manga de Yomu Sauna-dou

Tells the story of Atsurou Tanaka, a man who is ambivalent about visiting the sauna until one day he is turned on to their charms by the mysterious Mushi-Z ("Steamy-Z"). Atsurou develops a passion for saunas, and he travels Japan visiting various saunas and having conversations with other sauna enthusiasts like Guuzen-san ("Mr. Coincidence") and Ikemen Mushi Otoko ("Handsome Steamy Man").

(Source: Crunchyroll)