I Wanna Do Bad Things with You, Vol. 3 (manga)

After a stay in the hospital, Fuji returns to school with a new prank in mind: outperform Koichi on an upcoming test! Confronted by this seemingly insurmountable task, Fuji ropes in the pair’s charismatic classmate Kei to tutor Mamori. But when Kei develops a fondness for her new pupil, she sparks a rivalry with Fuji as both of them fight for Mamori’s affections.