help on yukki slack

hey im stuck on yukki slack
can anyone explain the slack spinning portion of the trick

Firstly, the poll isn’t nessesary. I know this is one of your first posts, but keep that in mind for the future.

And for the question; Practice. Don’t forget to keep the pinch.

Also, what exacly is happening? Is it not slacking? Or is it geting tangled so you can’t do the rest?