OldAvatar is right...
It's basically: "Whatcha doin', ____*, How's the birdie**, yo, I'm gone, I'm gettin' bored."
*) "mânca-ţi-aş" -- this is slang, and literally means "Eat you," but it's not really the same as the English "bite me." It doesn't mean anything, it's just a filler.
**) "birdie," unless you're a girl and you don't happen to have a canary or a parrot, in which case you just got yourself a nice little very rude word.
(Are you sure that's a friend who sent you this?)