Abstract: A device for controllably retaining a liquid to prevent spillage when the bottle is tilted or inverted for positioning the bottle to discharge the container's liquid contents into the intended orifice. The hydraulically operated plug forms an air tight seal with the smooth inner surface of the neck of the container, permitting the container to be inverted and positioned over the intended receptacle without releasing any fluid. Upon squeezing the flexible container, the lid is forced from the container by the hydraulic pressure exerted on the inner surface of the lid, permitting the liquid to pour freely from the container into the intended receptacle. A tether attaching the plug to an exterior location on the container allows the plug to fall clear of the stream of flow while preventing the plug from becoming lost.