A Sister's All You Need

A Sister's All You Need is a light novel series that received an anime adaptation in 2017.

The story follows Itsuki Hashima, a light novelist obsessed with little sisters, strictly focusing on them when he writes his stories which have praise from a niche but strongly supportive fan-base. However, despite his personality and interests, he is surrounded by a tight circle of friends and together they play strange games, go on spontaneous journeys and celebrate each other's successes.

Episode 2
Itsuki is naked while acting out a character from his latest volume, and later he opens the door while wearing just a towel.

Episode 3
Itsuki imagines a scene from his latest chapter.

Episode 5
Itsuki and Setsuna go to a hot spring.

Episode 11
Itsuki and his friends play an erotic board game.