Houkago Saimin Jutsu no Renshuu Shitetara Class no Gal ga Kita.

Three boys from class were practicing hypnotic magic in an empty classroom after school—once every other student had gone home. Just then, one of the “gyaru” in their grade poked her head in to retrieve something she’d forgotten. Spotting them, she grinned and said, “Hey, can you cast that hypnosis trick on me, too?” Caught off‑guard and unable to admit it was just a joke, the boys went through the motions of chanting and waving their hands as if performing a real spell… But to their astonishment, the gal proved unbelievably susceptible to their “hypnosis.” She melted under their makeshift ritual far more easily than anyone else ever had. (Source: DLsite, translated)