"Dude, I just ate a really hot pepper.. My NARF is on fire!"
The narf may be executed out of spite, for general annoyance or for general pleasure.
Narfs are best performed on younger sibblings, but in some cases, two younger brothers or sisters may attack an older sibbling for a rare, but exciting, double-narf takedown.
Catching an open-mouth narf is rare and can be dangerous.
Do you want a narf? I think it's time for a narf.