“OAA has no-one pissing in her cheerios. OAA needs no-one pissing in her cheerios. She pisses in her own, and defies the world!”
As is explained in this light-hearted thread, “OAA” stands for “Overly aggressive anon, motherfucker!” Further:
“OAA is not one particular nonny. It is more like a trophy you get to keep until some other person picks it up and becomes OAA.”
“You can be OAA. I can be OAA. We're all OAA sometimes.”