Sloope Duke

When a girl's ass is so flat that it looks as if to be a continuation from her back, straight to her thighs. When the back pockets of her jeans are touching. A.K.A. completely lacking booty.

Damn dude, that girl got a Sloope Duke. Her as is so flat, when she lay's on a table, her entire backside touches.
Where is her ass? Its GONE!!