The typical posing called "headbanging". Only if you wear long hair, while metal music is playing, you put your head down and shake it shake it shake it... this is typical for hard rockers, gothic and dark guys who never see the sunlight in a smoky, sweating and smelly pub, moving hysterically in front of the stage and claiming their isolation behind a hair curtain.
But it was amazing here instead, seeing this done under a bright sun, by sweet, multicolored 13 years old gals, happy and joyfully... this reminds me how the music comes here from the west and it's immediately filtered and devoided from most of its original content, transformed in some disposable good which will be replaced by the next song next week.
In any case, I 100% prefer happy gals headbanging rather than the darky wanna-feel-deep-and-lonely western guys doing that.