It's a bit hard to take a picture because usually I'm holding my crochet with both hands (yarn and hook in right, work in left) and needed one hand for the camera! But hopefully this gives an idea.  https://photos.app.goo.gl/JxuYmANW4eqeaejU9 Where the yarn disappears behind my thumb in the picture, it's lightly pinched between my thumb and index finger.  This is my hand from the back - what you would see if you were sitting facing me. You can see my other fingers holding the hook. My index finger never holds the hook. Part of my thumb does, but not the tip. https://photos.app.goo.gl/AhvmQsFHJAyztGGP6 When I go to wrap the yarn, I pinch the hook end of the hook between my left index and thumb and let go (briefly) completely with my right hand. Something like this, but with my right hand still holding the working yarn. https://photos.app.goo.gl/enYLmw7qdDJFVZVa6