How to escape from China's got talent show

In the past, there was an explanation for this kind of magic. In fact, it doesn't need any props, but it's just a trick. Anyone can do it ~ before tying hands, cross your chest, inflate your lungs, and the most important thing is to put a fist under your arm with one hand ~ after the performance, loosen your fist and inhale, and there is a gap in your clothes. Then he takes off his other elbow first, and then crosses his hands from head to back, so that he can completely free his hands ~ there is no difficulty below ~