Berf' Quake

When thicc girl such as a PAWG shakes her large glutius maximus aka Berfday cakes (Birthday cakes) during a twerk or similar dance move and the shock and ripple effect that takes place is known as a berf quake.

2 guys at a generic party....
Guy1: Oh shit do you feel that?!
Guy2: Brace yourselves!!! BERF' QUAKE!!!!