So what makes this [the 8] work for you? It’s the friction of the string on the instrument. So if you hang it and make it do a lot of twists, it makes a C here, a C here, and a U here.

If you pull it like this, it’s completely closed; if you simply widen it, you see it go down. So if you reduce the U and make it a C, it slides.

You don’t need to push the string in, just let it slide a little. The closer you bring it to your body, the more it stops, so you push it away and go down.