Can you feel it from behind?

Seojun is a very popular college student with guys, but he always seems to have bad luck with girls. During the opening general meeting, he tries to mix in with some girls, but their attention is on Yunwoo, one of his schoolmates. Feeling frustrated and envious, Seojun drinks a little too much. He suddenly woke up and felt something different about Yunwoo—Yunwoo seemed unusually gentle. Suddenly, something odd attacked Seojun, and he could hear from the back, “Seojun Hyung, can you feel that?” Seojun became discombobulated. How was it like this?.