Well the infamous question has finally been answered!
how did Jikook go from hugs and hearts in 21st century girl stages, to rubbing on chests and spanking booty?
Min Yoongi spanked Jeon, Jimin didn't appreciate the lack if consultation before hand and made a few tweaks to their part to remind Jeon and anyone else that, that booty belongs to him. Jungkook enjoyed the sight of his Mochi getting all possesive of him, and agreed to the change.
But this is Jikook.
So it quickly evolved from Jimin trying to mark his territory, to Jikook full on flirting, "subtle" on stage confessions and so much touching.