From one couple behind another: Do a 3/4 Zoom and the (new) leads Quarter In. This is the same as Zoomeroo above which in turn is the same as Three Quarter Zoom and Quarter In. Zip Out is a Three Quarter Zoom and Quarter Out. Zip Right/Left is a Three Quarter Zoom and Quarter Right or Left.
COMMENT: The "Zip" refers to the action of the lead dancers which is similar to the "Zip Code" action.