This word came from a meme video in Vietnamese community where a guy screamed "thèm bú lồn quá" So everyone took the "bú lồn" and use it as "bulul" which mean "LickVagina"
A lot of people in a confined space like a train, classroom, fair, park, etc. The bululu word comes the noise produced by the large number of people confined in that limited space.
There was a bululu in the train (no more people were possible in the train even standing as it was full)
The party was a bululu. The fair was a
a unique organ with high vascularity that not only serves as a cushion (like a butt) but also processes information and transmit communication signals when necessary