It was first said in the Golden Girls season 7 episode 19 and to get in a good laugh you mention something to do with Joe and they'll ask "who's Joe" and then you scream "JOE MAMA" and then everybody laughs
Person: god this food is delicious
You: oh man Joe would love this
Person: Whos Joe
You: JOE MAMA HAHAHAHAHA
<I heard Joe made it onto the Basketball team?> <Who’s Joe?>
<JOE MAMA!!!!!!!!> <BOOM ROASTED!!!!!!!>
Joe mama with anotha father and ur uncle beating you to go to school...
1: You know Joe?
2: No, who's joe
1:JOE MAMA!!!
2: Dies of death.
Person 1: Hi Joe!
Person 2: Who's Joe?
Person 1: Joe Mama
Person 2: ...
"I met joe today." "Joe who?" JOE MAMA IMAO BOOMER XD