Nice variation of corkscrew/bondage! Gustavo always has amazing control of the top.
I just tried the trick (with a bearing, not a fixed tip as he does) and it is more difficult than it looks.
To a question from one of the kids (that I cannot make out) he answers that the string he is using is pretty short and it makes it more difficult (perhaps the kid was asking for more wraps?) Anyway, Jim, with a longer string perhaps he would have better "aesthetics"