Super one-handed Kan-CHO!!!!!!!!!!

ouch!

Kancho (カンチョー, kanchō) is a prank often played in Japan it is performed by clasping the hands together so the index fingers are pointing out and attempting to insert them sharply into someone's arse when the victim is not looking.
So popular is Kan-CHO! in Japan that there are even anime's featuring Kanchot (such as Naruto, where it has been called the Thousand Years of Pain).They even have a TV gameshow where a celebrity kanchōs random people!