@beforemeteor
9S didn't know this guys name, or what his problem was in general, but at least he agreed to having someone watch him pierce himself.
9S wasn't exactly intending to be that person, but... well, whatever, it's not like he had anything else to do. That's the strange thing about peace-- there is so much... free time. He really doesn't know how to fill all of it, so this works.
He follows the silver haired human quietly, because the guy seems disgruntled as it is. 9S isn't expecting to just be let into his home, either, but humans must really be trusting in this day and age! How spectacular! He always read that it was possible, but that most humans only trusted people they were well acquainted with-- not total strangers.
So with the piercing kit pieces on the coffee table, rubbing alcohol and tissues and two studs, 9S watches as the human uses a skin safe marker to make two dots, one on the center of each lobe where he will pierce it. Except he definitely isn't placing them in the middle.
"Um... no, that's not centered. Either one of them."
9S offers a small alcohol-wet napkin for the stranger to wipe off the marker and try again while glaring into the small mirror on the table.