Oh, so they're actually a real thing, it's just that they flirt and have fun. Strangely realistic, albeit a rare relationship phase.
Also the amount of people treating this webtoon with generic shounen pseudo romance shit tropes is a little bit dismaying. They're adults, you know? The don't 'not realize it yet,' lol. The reason why adults don't really like teenage romance drama is actually because of how simple it is.