Remove your old strings. Put a string winder on the machine and turn it to loosen them, then pull the ball end of the string out of the bridge. Slot the non-ball end of the string through the bridge, over the fret board and into the hole on the machine head. Tighten the machine head with the string winder. Connect a quarter-inch cable between your bass and a chromatic tuner, turn the tuner on and tighten the string until the tuner tells you it is in tune. New strings create a bright, "zingy" sound similar to Flea's distinctive tone.
Tighten the screws on either side of the bridge on your bass. This lowers the action of the strings and makes it easier to play slap-style bass, as you need to apply less pressure to the string to sound the note. Use a Phillips screwdriver or hex-key, depending on the make and model of your bass, to turn the screws.
Press the third fret of your E string with your first finger to make a G note and slap the string with your thumb. Flea achieves the distinctive funky playing style heard during the verse to "Aeroplane" and intro to "Higher Ground" by slapping the low string hard with his thumb. This technique creates a punchy, percussive sound.
Pop the D string with your first finger. Place your third finger on the fifth fret of the D string to make a G note. This note is eight notes, or an octave above the G you are playing with your first finger. Crook your right hand, first finger slightly. Snap the D string upwards and release it so that it twangs. In the same movement, mute the string with the fleshy part of the side of your hand, just below your little finger. This cuts the note off dead. Perform the pop directly after the slap.
Slap an open E string, let it sound for half a beat, press the first fret and slide up to the twelfth fret. The slide takes in all twelve half-step notes between low E and the next highest E. In the Red Hot Chili Peppers hit "Give It Away" Flea plays a riff where he slides up the strings to reach higher notes. This is unusual because it's easier to reach the same E note by playing the second fret of the D string. However, the slide creates a loose, funky vibe that sits really well against the drum groove.