スレイブ or ラバーズ～幼馴染隷属日記～

Emi Sawamiya is the classmate and childhood friend of the protagonist, Yuichi Kariya. From a young age they have competed for the best grades. However, Yuichi has often won, and Emi is unconvinced. After school one day, Emi called him to a less popular place and declared that they compete in the next prefectures mock exam. If he loses, he can listen to what the other party says for a week. Time passed, and the results of the mock test results were announced. Yuichi won by a close margin. Then he gets an erection, which angers Emi.