I'm The Angelic Midnight Demon

Fujiki Tomo is a teacher. His class has a new student who is as cute as an angel: Shiina Kazunari. But whenever Fujiki sees something unbelievably cute, he can't help but have an incredibly fierce and scary expression on his face due to nervousness. This scared Shiina a lot… and just as Fujiki is trying hard to fix this problem, a second "Shiina Kazunari" appears in front of him at night. He stole a kiss from Fujiki, and said: "I fell in love with sensei today, and couldn't help but come and see you." The smiling person in front of him wasn't the angelic Shiina, but a seductive young demon!