The best way is still the vet hold or to gently but firmly restrain the head just behind the jaw or if confident, the top and bottom of the head. It takes time but once you do it a bit, it becomes easy. The reason this is the best way is it allows you not only to keep the snake from escaping but allows you to better position the snake by working with their coiling to straighten the body.

I saw a tube being used on the show about the Bronx zoo where they had to retrain a cobra but that was because well venom but for snakes that are not huge, the vet grip is still the best method.