18+ Boku dake Shitteru Ichimiya-san

As a guy with no real friends, Nishina has spent months just watching Ichimiya Misumi who sits next to him in class. At first glance, Ichimiya looks like a lonely girl without any special appeal, but only Nishina knows how provocative she can really be. Upon realizing that Nishina is watching her, Ichimiya begins to interact with him in her own unique way. But unbeknownst to Nishina, Ichimiya also seems to be harboring a secret...

(Source: MU)