If I'm playing fingers, I anchor my thumb on the pup. Only time I chance position is when I'm slapping/popping. When I'm popping (which occures primarily on the D and G strings) I rest my thumb on the E, and partially on the A string, both right next to the neck. And Picks? When the portal to the other dimension opens up, for that brief second in time, I grip the pick, and non of my fingers make contact with the other strings...
Pretty standard I guess...
Pretty standard I guess...