upper and lower lips banged together
The Bilabial Percussive Generator is made by banging the lips together. Although they don't make much noise on their own, by creating a small vacuum of air in mouth a popping noise can be made (although strictly speaking this would be an inward bilabial plosive!)
The following diagram shows where the Bilabial Percussive is made in the mouth.
This iconophonic isn't currently used in any BZZKTT sound.
BZZKTT Version 8.2 • © 2015-2020 Gavin 'Beatbox' Tyte (aka TyTe) • All Rights Reserved
BZZKTT is kindly hosted by Alex Tearse from Reefnet.
Special thanks to Alex Tearse, Paul Arnett, Michael Wyatt, Tyler Thompson, Helen Tyte, David 'Goznet' Gosnell, and Jerusalem Productions.