^ I know a lot of boys his age who have the same body type too, he just hasn't hit his growth spurt yet so it's not very worrying. Heck I'm sitting with my boy cousins right now and they have skinny arms like this. I just hope Johnny doesn't force them to diet when they grow older to look like their seniors though D:
btw their song is actually pretty catchy, nothing ~erotic~ or whatever, just bad engrish
Here's a live if anyone's interested:
They all look 11-12 though so XD