The trick is simple . they attached a string to there mask. and the other hand is pulling the string when they move. . . That trick is quite fast. . That's why i amazed to them.
Oh wow they're using their hand and grabbing it from under that cape thing ( sorry not sure what it's called) and they're just dropping it into their shirt. Super interesting though. I literally just found out this even existed.
The principle is very simple: the thin mask gets pulled into the collar, each time. But the artistry lies in how the principle is applied to create an effect. It's like everyone can cook food, but some chefs transform the ordinary.
With new technology it is even easier than before all they need is tap a button on the feet and a electronic device pulls the face mask one by one as fast as u can push the botton
It's still a magic. You even don't know how it works if you can get the clothes and their props. What's more, you don't know how they put on the masks again after taking them all off. That's why they don't care show in front of the cameras.