(Credits to mah friend who came up with this assumption)-I assume that JK once used a rolled up suga in a blanket as his punching bag and was then killed by suga for ruining his sleep-
Jungkook: Well since I am alive the assumption isn't true. First of all, I'm terrified to touch suga hyung. Second of all he has a passcode lock on his room, so for me to get into his room and then roll him up and use that as a punching bag seems like a suicide mission.