Slap Bass – A bass guitar playing technique which involves both pulling up and off with the fingers, while 'slapping' the strings, with the thumb to create a musical, percussive sound
(Pronounced slap bays)
To remember what slap bass is, it's essentially in the name:
Slapping the string with your thumb and then pulling the string with your index finger creates a percussive sound along with the note that is fretted further down the neck
Hand position for the slap bass technique. Note the use of the joint halfway up the thumb (where the bone is thickest) to slap the string. The index finger is curled under a lower string, ready to pull it and create a popping sound to accompany the slapping.
The slap bass technique was originally developed to imitate a drummer, with a rhythmic sound that cuts through the sound of a full band, far more than a bass guitar usually would. It has since become a signature sound of the funk genre.