When someone's laugh sounds like a machine gun and the surrounding friends bust out their air machine guns until said laughter ceases, typically perpetuating the laughter and the air machine guns!
The joke was so good, she busted out her hachine gun, leaving collateral damageeverywhere.
Hachinpa is a term used after someone says something that you don’t believe. It is short for “100 Percent”. This term is often used in a sarcastic manner.