Big ass is a way of saying dumbass or idiot
It was created by rack00nz in a PS4 party
Whilst he was playing call of duty cold war.
"Isn't Brazil in Africa?"
"Ur such a big ass bro"
"AHHHHHHHHH"
"Shut the fuck up you big ass"
"This girl just rejected me"
"Yeah cause ur a big ass"
IT MEANS DAT UR MUMMY HAS DA BIGGER ASS
STOP SEXING WITH UR MUMMYS BIG ASS