Ayame-senpai wa Boku to Himitsu no Keiyaku wo

An ordinary high school boy, Daiki Mitsuya, found a girl covered in wounds on his way home from school.
She has animal ears, and after licking his ears, she ran away.
He began to wonder if it was all a dream, but then Ayame Sakuragami appears...!
Ayame told Daiki about the potential power of his ears, and she felt responsible for getting him involved. So she proposed a vow of absolute obedience to protect him at all costs.

(Source: Comic Gamma Plus, translated)