A Girl on the Shore (2021)

Two junior high school students enters a casual sex relationship.

Keisuke Isobe and Koume Satou live a rather dull life. But when Koume's crush breaks her heart, their situation becomes quite unordinary. She starts a "no-strings-attached" relationship with Keisuke, whom she had previously rejected, both finding solace in the other in order to fill the emotional voids in their lives.