Well, it does have meaning in that the top is being very attentive to the bottom~
In the panel before, of top’s face, there’s the three lines which means he’s noticed smth. Then, in panel of bottom, the first sfx is jjaeng-, which is used to denote intense, blinding sun glare, followed by ttakeum ttakeum which is like “stinging” or irritation (and it shows Minchae squinting his eyes/lifting hand to them). Then in the next panel, where top moves to stand next to him, there is seu-eok which is “shift/slide,” showing the top has moved subtly to Minchae’s side

In chapter 5, the sfx isn’t translated, but the sun is bothering bottom’s eyes and the top notices this and stands next to him to blockit