A collaboration series between the "Doujin Circle U-Dash" and "FunCity"! A female teacher nicknamed "Iron Mask" by her students for her seriousness is influenced by an exhibitionist woman she happens to encounter, and becomes addicted to wandering around the school naked, becoming addicted to the pleasure of shame... Contains 9 scenes in which her body throbs with shameful pleasure while wandering around the classroom, gymnasium, and school! 01. The serious "Iron Mask" and the "Exhibitionist Woman" 02. Masturbation with conflict in Sumire's room 03. Naked masturbation on the stairs of the school building 04. Provocation with a miniskirt and no panties during class! 05. Self-exposure nude photo shoot on the roof 06. Posting selfies in the classroom... 07. Being found out by a student and having sex in the gym storeroom 08. Falling into raw sex in a humiliating volleyball match 09. Semen-covered classroom restraint gangbang!