Hard to say~ I'm guessing it's because sitting like that can be quite uncomfortable to those not accustomed to it while keeping good posture so he could be feeling it so to speak but that easily also could mean he simply needs to pee really bad XD I'll stick with the he's not used to that sitting posture yet and it's getting unbearable :p
Hard to say~ I'm guessing it's because sitting like that can be quite uncomfortable to those not acc
