The Lovable Player

During their school days, Jae-Woo and Hyun-Min were each other's equal. Hyun-Min receives a special gift from Jae-Woo and is convinced that it's a green light for both of them. However, when Hyun-Min witnesses Jae-Woo giving the same gift to another girl, Hyun-Min becomes convinced that Jae-Woo is just a swallow who flirts with anyone and distances himself from him. Six years later, the two reunite at a class reunion, but Hyun-Min still feels uneasy about Jae-Woo. But...

"Senior. The last train has already left. Can you let me stay for just one day?"

What kind of shameless kid is this?

(Source: Lezhin, translated)