A fully and continuously vented drinking cup or container for infants and children, which consists of a vessel or container for containing a liquid or formula, having a resilient spout which rests upon its uppermost edge. The interior aspects of the feeding spout, and the feeding diaphragm, are all molded so as to arrange the diaphragm slit, or opening through which the liquid flows, in a position that will be vertically aligned between the lips of the infant feeding, to thereby allow the infant to open the spout and allow the liquid to flow, just as if the child is drinking from a cup. The diaphragm may be shaped concavely, with respect to the structure of the feeding spout. A cap firmly approximates the interior aspects of the feeding spout, and applies it to the top or upper edge of the container, whereby a leak proof seal is formed therebetween, but yet allows air to enter between its retaining collar, and the vent tube and reservoir tube, to allow air access into the container, as liquid is being drank therefrom.