From Lovers Dream:

Alone and dumped outside of a love hotel, Mitsuka finds herself caught by the last person she wants to see--her school counselor and teacher, Kaga-sensei! Instead of turning her in, Kaga-sensei wants an interview. It turns out he's an erotic novelist, and he's looking for just the right dose of high school girl reality for his latest work. Kaga makes it clear their relationship is strictly business, but can Mitsuka keep it that way when she's falling for her teacher?