Kateikyoushi no Onee-san The Animation: H no Hensachi Agechaimasu(2007)

Based on an adult game by Atelier Kaguya.

Touya returns home during summer vacation to find 4 older women (Rio, Nagisa, Amane and Sara) awaiting him. They have been hired as live-in home tutors for Touya. However, his lessons are not limited to book-learning...