Commonly used by people from or around the Detroit area. It is really suppose to be pronounced "Wut Up Though" but is said like Wut up 'Doe', it's just a phrase used by many detroits to say wut up.
*CHRIS WALKS INTO A GAS STATION*
Chris: Wut up doe!
Arab behind the counter: Wut up doe my baby!
Chris: Shit chill'in let me get too loosies.
Arab behind the counter: Ight my baby be safe.