Tsugou no Ii Jirai-kei Kanojo to Karada Dake no Kankei wo

A person meets a girl online named Lyon, who plays games in her underwear despite them never having met. They interact often for activities like gaming, going out, or eating late-night ramen, but they do not know each other's real names and are not close. The speaker finds the arrangement comfortable. They also have a cousin and a junior coworker who are described as "landmine-type" girls, and both express interest in having a similar casual relationship with them.