Otona no Jikan

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 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?

(Source: Lovers Dream)

Included one-shots:
Volume 1: Soshite, Kimi wa Boku wo Suki ni Naru
Volume 2: Koisuru Sata mo Kane Shidai
Volume 4: Tatoeba Namae wo Yobareru dake