How to Position Your Right Hand for Slap-style Bass Guitar Playing
If you know how to properly position your right hand for slap-style playing on the bass guitar, you'll be able to produce a wider variety of sounds. The idea behind slap style (or thumb style) bass guitar is to strike a low string with the side of your thumb, giving it a percussive sound (a sharp attack and decay of the note, like a drum), and then to snap (or pop) a high string with your index finger.
Make a light fist with your right hand.
Lift your thumb away from your fist, as though you were hitch-hiking.
Loosen up on your index finger and create a hook.
Your index finger should look like it’s pulling the trigger of a gun.
Rest your forearm on the body of the bass.
Your right hand should hover above the strings.
With a sharp twist of your wrist, flick your thumb against one of the low strings, striking it at the very end of the fingerboard.
You strike down toward the fingerboard, not toward your feet. Make sure that you lift your thumb off the string immediately so that the note rings.
Hook your index finger under a high string, and with an opposing twist of your wrist, snap the string against the fret board.
Don’t pull too hard on the high string, or you may break it. Only a small amount of force is required.