SDAG

This is use as an abbreviation for "Shake that Ass, Girl".

S : Shake
D : Dat
A : Ass
G : Girl

Could be also used as STAG, STAB (Shake that Ass Bitch" etc.

Chat Room
Boy : Hey girl, open ur webcam and sdag
Girl : Sure, u'll go made when u see my hot sexy as!
Boy : Well, v'mon go ahead sdag!

and many other examples