I got this from the manga 'Immortal Rain' by Ozaki Kaori. The guy in the white lab coat sneaked up to the one in black garb and ran his finger down his back, making him go AAAAAhh! See how his back is curved into an S shape? I think it's so funny and a bulb kindda went off in my head. *evil laugh*
And so..I decided to experiment on my sis to see if she'd go S-shaped too. Today, when her back was turned towards me, I acted immediately. Unfortunately, in my eagerness, I pressed too hard. She did go AAAAhhh! and went S-shaped but she turned and said "WHAT ARE YOU DOING?? THAT HURTS!" >__< and she was looking at me all confused. I got shocked too since I thought she wont have felt the finger too much over her thick jacket. But seeing her confused face and remembering how her reaction was EXACTLY like the guy in black garb, I had to laugh. God I am so evil.
Now you know why I did what I did, bi.... LOL!