Seishun Buta Yarou wa Petit Devil Kouhai no Yume wo Minai

Sakuta may have cured Mai's Adolescence Syndrome in the nick of time, but now he faces a no less harrowing task-convincing her to officially date him. After managing to win that round of verbal fencing, he gets some well-deserved rest...only to wake up "yesterday," with all his progress reset. This inexplicable phenomenon seems to be centered on Tomoe Koga, and the only cure is to...pretend to be her boyfriend?!
(Source: Yen Press)