whaa-whaa
It means you are whining like a baby:mocking someone as a way to be unsympathetic to that persons issues at work.
Oh, "whaa-whaa", poor baby has to work for a living just like everyone else quit your whining!poor
Pissy Whaa Whaa
Used to describe little children on Call of Duty who grudge kill and little kid rush after being repetitively killed by your player. They often rush the spot they were killed in the hopes of finding your player.
"Oh wow that poop kid just went pissy whaa whaa on me because I killed him 4 times"