A nipple assembly is removably attachable to a baby bottle via a retainer ring and comprises a nipple having a flow aperture through one end, and a nipple flange structured to support the nipple. A flow control valve assembly is mounted to the nipple flange and extends inwardly from an inner surface of the nipple flange, the flow control valve assembly is structured to allow pressures to equilibrate between the inside and outside of the baby bottle, without allowing fluid to leak therethrough. A training cup spout assembly is removably attachable to a cup and comprises a spout having a spout channel extending therethrough. The spout channel has a dual valve assembly mounted therein to permit flow for drinking, as well as to prevent leakage of fluid from the cup. A flow control valve assembly is mounted to the training cup spout assembly to permit pressure equilibration.
