whoever spelt "du" as "dou" is a dumbass
the phrase originates from south vietnam.. you might also here "dit me may" which means the exact same thing, but is used my nothern vietnamese people for their dialect is slightly different by means of accent and a few words.
DU MA MAY means fuck your mother..
DU MA means mother fucker..
a multi purpose phrase that vietnamese people use for almost every meaning but most commonly used in lieu of "hello, hell yeah, hell no, i want to fuck, any curse word, im hungry, hide, gimme that, good night, and order up"