Konohana Link Mangaコノハナリンク
From Okazu: Two stories parallel each other. In one, a student confesses to her sempai, in the other, new student Suzuki Chieri comes to the school. The two girls are kissing when Chieri sees them, as she walks around the school. But, as she watches them making out, she can't help but notice that one of them is looking back at her!