The figurative act of putting a banana in one's ear.
Pbye is the achronym for: Put a Banana in Your Ear.
This expression is nowadays used by Italian people as something to say when you don't want to ear something bad, so it's used to ask people to shut up, to quit saying stupid things in a polite way (because there's no gross word in it), in case you don't agree with what the other person say, or just don't care.
Sometimes it can be used to mock someone who's not present, but always in a respectful way.
It's origins are referenced to the well-known request made to Charlie the Unicorn to put a banana in his ear, so not to hear the bad in the world and to let the sadness disappear!
"the bad in the world is hard to hear when in your ear a banana cheers, so put a banana in your ear."
1- Eric just told me off again because of my failed attempt to fix the printer.
2- Eric pbye! ... He don't even know what a printer is.