Ushiro no Seki no Gyaru ni Sukarete Shimatta -Mou Ore wa Damekamoshirenai- is a Manga/Manhwa/Manhua in english language, Comedy series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.nl fastest updating comic site. The Summary is

Comedy, Ecchi, Romance, Slice of LifeMy school life has changed drastically just because she likes me that I barely talk with?! Yuizaki Shino, one of the most beautiful girls in the school is a classmate of Fujiwara Sandai sitting behind him. It was only on a whim that Sandai helped her out despite spent his days studying and not having a single friend. It was supposed to be― "I couldn't wait for after school! ....Hey, hold on a minute?" That day and moment led Sandai to start dating Shino. They spend time together after school, they keep up with each other's hobbies, and they stay over frequently.... She's kind-sweet and always clings to him. And somehow, the other classmates started to pay attention to Sandai, they slowly changing his style appearance, and there was a lot of talks around his belt. He's more unsettled than when Sandai alone before. ....Well, this kind of school life isn't so bad, is it?Manga