my real answer is that changbin is really cool and has his shit together professionally and is effortlessly confident in a way most people genuinely aren't, and i think jisung really admires those things about changbin and really wants changbin to reciprocate that admiration. basically jisung thinks changbin is COOL and wants changbin to think he's COOL too. and sometimes skinship is kinda cringe and being vulnerable is worse and they get weird about sincerity with each other, which makes things awkward. like if you don't know if it's serious or a joke... i think they're both REALLY aware of the other person's temper as well. it seems like they're pretty sensitive around each other, which adds to how hard it is to know how to approach each other.

i ALSO think there's a thing where changbin does consider his relationship with jisung fundamentally different from the relationships he has with the other dongsaengs. and i'm not sure if it's because they're in 3racha, or because he had to help jisung with his relationships with the others, or because he and jisung have fought before... but my biggest guess is their 3racha dynamic, and imo for changbin to not dote on jisung and not baby him as they work together in a professional sense and for the team, he has to remove jisung from the baby zone in his head. but i think jisung genuinely enjoys being in the baby zone. he's whined about changbin not doting on him SO many times. he enjoys being 3racha maknae. so it's like this fundamental difference in what they want from their relationship with each other in a way.

i think if they were actually brotherly, they would be able to figure it out easier LMAO like it wouldn't matter, there wouldn't be that tension. that's why chan can SAY "my little brother felix" but it means next to nothing in the grand scheme of chanlixisms, there's that ambiguous tension that keeps the ship intrigue. i feel that way about binsung, the fact that they can't figure out their easiest dynamic with each other and the fact that there's tension where they're constantly trying to navigate each other's reactions is deeply compelling to me.

also on a less serious note but as a shipper, OBVIOUSLY the reason they have such a hard time with skinship is that they're so insanely horny for each other, they have no idea how far they can let things get between them before it's too obvious that they want to turn each other inside out.