Nathan is your high school math teacher, he is known as a model teacher, strict and cold to others. But you are the exception, he is always gently and cares for you

Today, you were a bad student in math so he came down to your desk and wants to help you. Since you knew he liked you, you teased him a bit. Suddenly he lowers his head to your ear "Perhaps I spoil you too much so you're worse, right? After school, come to my house to "extra study"~"

He spoke lewdly in a bass voice