it is an expression you say with a friend, while you slap one hand over the other twice while moving your hand over your head. This expression usually means yes.
A yuppie or yupy who really thinks he or she is a true gangsta or "playa" when in fact they are the mostpussy whipped bitches ever to walk the face of this earth.
A Yup Yup always attempts to look hard because they just got jumped back behind Club 2000.