One designated couple will split the opposite couple and go around one to a line and then the line steps into the center (H-formation). Inactive couples now do a "Right and Left Thru along the Line." Line of four backs out and the ladies "Sashay Right." Bend the line and back up to new lines of four (parallel lines). Designated couples step forward and "Reel the Line" by doing a full right arm turn in the center and then going (each to the opposite line) to left arm turn the nearest inactives to return to the center to turn partner by the right arm once and a half to turn the (opposite sex) inactive with a left arm, then go to partner for another right arm turn, finally going back to the line to corner for a left allemande.
This definition is from The Handbook of Modern Square Dancing by Jay King.
It is provided here for informational and educational purposes only.