Natsu Doki! Harem ~Shinsekitaku de no Nayameru Juken Benkyou~
Original title: なつドキ！ハーレム～親せき宅での悩める受験勉強～
Yuto failed a university entrance exam. He needs to study hard, but he is still down.... One day, his mother tells him to stay at Shizuru's house and study hard. Shizuru is his aunt and ex-teacher. When he arrives at her house, Shizuru and her daughters welcome him. He is surprised to see his beautifully grown up cousins. He soon decides to study hard there, but there are a lot of erotic temptations surrounded by beautiful girls....