It is the combination of Wahh and Nigga. Wahh, is a phrase an Asian person says when surprised. Nigga, is what black people call each other as in homie. Thus, this is what you call Asian person with a black personality.
Yo, Chung Lee is the waggah, he smoked 5 joints and fucked all the hos at the party yesterday!
Pajama casual is a term used when working from home and preparing for a video conference. All business above the waist and your pajama pants down below.