Ougo Mitsunaga wa Namagoroshi ga Tsurai

Overview

"When I turn 18..." Mitsunaga will grant a wish of his cute girlfriend Karen(!?), after adding layers and layers of endurance. Even though he is an untalkative and diehard person, he has a bit more sexual desire than the normal person so there's no helping it for him to expect something. However, something unexpected happened on their memorial day that should've been celebrated!? She's precious so he won't lay a hand on her but because he likes her, he wants to touch her more...a troubled pure love story of a full-grown man! Note: The chapter count includes 1 extra story.

Source: AniList