Thumbing Down the Back of the Neck

There’s a human, physical inclination for your thumb to become stuck on the back of the guitar neck as you move from higher to lower positions. You might try lifting the thumb off the neck as you make these downward transitions, you might use your guitar polish on the back of the neck to effectively grease that area, but my basic advice is to do what works for you so your thumb doesn’t hang-up higher on the neck as you move down towards the nut.

If your thumb does get stuck you’re liable to play wrong notes, because you’re no longer in a good position.