Just chiming in right quick:
“aa” as Charlamagne Tha God has said is a term of endearment while “er” is hardly used in the same way as it is usually used in a demoralizing way. There is a clear differences in the way both is used.
That’s all I have to say on the matter.
What about white people using the former?
Don’t mind it at all
Are you black?
Don’t know why I’m speaking for him but since it’s a legit question and I don’t want it to be buried I seem to recall him saying he was mixed, I don’t recall exactly though.