What is it?
It is a word you use to follow up a comeback and cement the victory.
Used especially for, but not restricted to, when someone makes an extremely witty comment about you and you come back with something utterly lame like 'Yeah ... well ... you smell. ZING!!!'
The ZING!!! ends the interaction and you always win. A ZING!!! is final.
It's appropriate anytime.
Specific to being Awesome Socially: if you're out and someone is tooling you, is too witty or if your brain just is not firing it can be employed as a 'get-out-of-jail-free' line. Make the lamest comeback then get up in their shit and hit them with a ZING!!!
Playfully.
Nearly everyone instinctively gets it when exposed to a ZING!!!
Everyone laughs, you win the trash-talk battle, you have demonstrated memetic high-value, it was all so easy.
Enjoy
And come up with your own silly phrases, games and traditions. Anything that amuses you.
Peace,
kowalski