Slapping and popping are ways to produce percussive sounds on a stringed instrument. They are primarily used on the double bass or bass guitar. Slapping on bass guitar involves using the edge of one's knuckle, where it is particularly bony, to quickly strike the string against the fretboard. On bass guitars, this is commonly done with the thumb, while on double bass, the edge of the hand or index finger may be used. Popping refers to pulling the string away from the fretboard and quickly releasing it so it snaps back against the fretboard. On bass guitar, the two techniques are commonly used together in alternation, though either may be used separately.

The double bass, also known as the upright bass, the acoustic bass, or simply the bass, is the largest and lowest-pitched chordophone in the modern symphony orchestra. Similar in structure to the cello, it has four or five strings.