A spout pouch, configured to removably couple to a feeding device, for feeding liquid to a child includes a spout having an inner surface that includes at least one feature selected from the group consisting of a ridge, rib, boss, recess, groove and step. The inner surface is configured to engage with a portion of the feeding device when the portion of the feeding device is inserted into the spout. The spout pouch also includes a pouch of flexible material coupled to the spout and configured to hold the liquid. Other systems, methods, and components are also provided.