A term used to describe someone who has a rather loud assclap while dancing or shaking hips.
You will experience Flongus if you have not practiced your twerking skills.
Jimmy: " Hey Jennifwa, wanna dance to Daft Punk?"
Jennifwa:" Sure Jimmy! My body is ready!"
*Jennifwa starts dancing to Around the World*
* loud clap sounds out of nowhere*
Jimmy: " Umm, Jennifwa, did you just Flongus?"