All things facing the scrotum. Point of origin. A direction that contains the polar perspective of the scrotum or "sack". The act of facing toward one's balls.
Tina has her face near Trey's crotch. She must be facing sackwards. When we drive towards that set of balls we are going sackwards.
Jim: "Hey! Listen to this dope bagpipe rock song I found!"
Pam: "oh I love bagpipe rock! It makes me want to drink, like a beer or scotch"
Jim: What a sackard.