Katara loves kissing his cheek🥺 she keeps doing it later in their late teenager years too, which also invalidates the argument 'she did it in the show as a sibling' or anything along those lines btw.
for once, SM & center 4 did something right. and that is to let sakuya & ryo act like regular teenagers & be free. i love to see them just being energetic, random, and full of life. since we can't stop agencies from debuting minors, the least they can do is to let kids be kids.