hello no worries i dont mind answering questions! their "sunbae" thing goes through several stages, but initially it starts as boyhood jungkook's shyness in front of yoongi as his crush/someone he looks up to. jungkook stage_chapter 1 is very young and polite and he can't allow himself to get closer to yoongi - so much unlike vmin who quickly form a bro/mentor relationship with yoongi. but as they grow closer, it just forms into this kind Thing between them. jungkook technically doesn't have to call yoongi sunbae anymore, but he does it because "sunbae" thing is also their reminders to keep it cute and behave properly. their struggles to form a proper relationship a lot of times relate to the distance between them, physical and hierarchy-wise: yoongi is older, yoongi, at stage 1, is more experience, yoongi holds a seniority over jungkook, they /can't/ be together. them holding onto this hierarchical status is like a secret & a promise - maybe, one day, when we can; for jungkook initially it's "once i debut", for yoongi it's forever "once i'm no longer haunted by myself". so when Yoongi starts to believe he's actually NEVER getting better, he asks jungkook to break it over them. and maybe he wants jungkook to believe for both of them for now that no, they actually can get over it. but jungkook stage 2 doesn't know yet what exactly holds yoongi back, so he just calls him hyung which hurts yoongi at the moment. (just got reminded how dramatic these two are LMAOOOOOOOOOOOOOOOOOOOOOOO) anyway i hope you'll be satisfied with my response!! i tried to explain it the best i could. maybe the boyhood lovers can help me out what makes sunbae special.