Mysterious Girlfriend X Vol 1

From the Vertical edition

The Ultimate Mystery: A Girlfriend! Mikoto Urabe is a new transfer student in Akira Tsubaki’s high school class. One day, Akira happens to find Mikoto passed out asleep on her desk after classes have ended. He wakes her and tells her it’s time to go home, and discovers that she has drooled on her desk. He spontaneously reaches out to touch and taste it… and then things start getting really strange. In this surprising and sweet twist on a high school romance story, boy meets girl and they learn about each other’s inner life through their highly unusual bond, and Akira learns to respect Mikoto as she sets a careful pace in the development of their relationship.

Source: Penguin Random House API