Bikei Shisho-san wa Zetsurin Nikutai-ha Nurunuru na no wa Mukimuki no Sei de Dekiai Saremashita!?

The handsome, muscular librarian with messy hair and thick glasses was my favorite reader! Mirabelle, who works at a cafe, actually has another side to her: an erotic novelist. In order to replenish the erotic passion she loved in her previous life, she made her debut as an author by writing her own novels. Her secret pleasure at the library where she always writes is observing the muscular librarian with his messy hair, thick glasses, and tattered shirt. She's so obsessed with his sexuality that she was trying to write a new novel with a character modeled after him. Alain, the librarian, found her, and just when she thought he'd be shocked, he said with sparkling eyes, "This is the setting material for 'Nuru Muki,' right?!" and "I'm a big fan of yours!" What's more, together with Alain, she spies on a couple having sex outdoors! The two share a thrilling relationship, but discover that Alain's true face is incredibly handsome, and that he's still a virgin as a result of his obsession. An erotic love comedy that will appeal to all readers' sexual preferences, featuring a sex-loving (virgin) erotic novelist and a handsome librarian who is a virgin but has become twisted!

(Source: Kadokawa, translated)