Wait what, did you read the raws or something? I thought the clench fist was cause Heechan smiled
no, it's the same chapter you're reading i assume (the latest english update here). i think it's a matter of interpretation? based on the gloomy/cold colours used for the panel, i don't think it indicates something "heart-fluttering" or "good" on minjae's part (i assume you're thinking more on this side, like he felt like minjae was v cute & he was suppressing his cuteness aggression haha). this manhwa uses colours quite well, so i assumed that the coldness was intentional. it could be because of minjaes smile though, but my own personal interpretation would be it's because he's mad he's gotta give up on that cookie cuz some bastards decided to stir up trouble during their date, so he's gonna give them a talking down, lol. i dunno though, can't wait for the next chapter :]
this chapter is genuinely so good & i love the relationship they have so i'm j being an impatient ass here but can we pleaaase get to the part of minjae beating up those guys who did that to jiyong? like i'm pretty sure that clenched fist meant he was gonna do smth about it right? there are too many of these bastards who need a beating, god bless we have minjae who can actually do smth about it