Based on the erotic game by Atelier Kaguya Bare & Bunny.

Protagonist Munetaka is invited to have sex with his girlfriend, Miran, at the Hotel Lala. Traumatised by his past, Munetaka fails his first time with Miran, straining his relationship with her. However, to help overcome his trauma, his older sisters and cousin intend to help by providing him with sex lessons. Between Ritsuka, Wakana, and Mashiro, who will Munetaka choose as his sex coach?

(Source: Translated and Edited from Nekopoi)