
They just have some misunderstanding with each other where the uke hear some rumors about the seme and around the campus the seme nickname is flaming cock. So the recent chapter is a flashbacks where the nickname came from. It's a funny story somehow because the story brought back to uke again because of his typo ε=ε=(ノ≧∇≦)ノ

Basically Gunjoon doesn't remember how they first met and how his drunk-text gave dude that nickname throughout their school. So because he can't remember, Gunjoon thinks it's a nickname associated with him sleeping around and being really good at sex. What we're seeing is Gunjoon being reminded where the nickname started.
What going on I’m lost I need to go back and reread it