Yuuka, who became a magical girl to protect her boyfriend, is preyed upon by her physical education teacher and becomes a prey to adult sex.
Yuka became a magical girl and protected her boyfriend Keita from her enemies (eaters).
At one point, she was witnessed by her teacher Sakoda, and her weakness was grasped.
To be forced into her sexual act-
魔法少女は寝取られる The Motion Anime, Mahou Shoujo wa Netorareru The Motion Anime