KissXSis - Season 1 Episode 6 Uneasiness at Akihabara

Unable to view and get porn from the internet using a PC their father won at a raffle, Ako and Riko decides to buy erotic games in Akihabara. But in the process Keita has to accompany them, so they devise a way to hide their real purpose for going to Akihabara. Ako distracts Keita by taking him to a cosplay shop whilst Riko investigates the 18+ section of a game shop. Whilst changing, they run into Ako's teacher, Yūzuki, who is a closet otaku (dressed as Mahoro from Mahoromatic Maiden). Riko later encounters her whilst trying to get a special edition game. After meeting Keita and being reminded about Ako and Riko's crush on him, Yūzuki drags him off to talk to him, inadvertently taking him to a cosplay-themed love hotel. After later being found by Ako and Riko, the group are encountered by Keita's kōhai and Yūzuki's younger sister Mikazuki, who covers for Yūzuki by stating she was buying the game for her.