It's called noodling. The fisherman doesn't hold worms in his hand. He gets in the river, reaches up under the undercut bank to feel if there is a catfish (or turtle) there. If there is, he just grabs it by the jaw and yanks it out (if catfish). Turtles require a bit more finesse. If you feel smooth shell, don't grab. That's the front and it will grab you back with a mouth made of basically scissor blades. It the shell is jagged, that's the back end. Feel for a tail and yank it out.