Application and assembly suited for use as a disposable leak proof child drinking cup

A method for maintaining a pre-filled liquid beverage in a disposable container assembly suited for use as a child's drinking cup with a passive closure system comprising the step of:

• a) pre-filling the container assembly with the liquid beverage;
• b) closing a lid on the container, wherein the top surface of the lid is provided with a drinking spout, which extends upward from the top surface and wherein the drinking spout is provided at its upper end with at least one opening;
• c) using the passive closure system consisting of at least one opening in the drinking spout of the lid that is sufficiently sized so that, when the liquid beverage is unintentionally positioned at the opening, the surface tension of the liquid beverage is sufficient so that the liquid beverage does not flow though the opening;
• d) drinking from the drinking spout of the container assembly by a child;
• e) simultaneously, using the passive closure system so that when the child drinks from the container assembly, the surface tension of the liquid beverage is sufficiently overcome so that liquid beverage flows through the opening;
• and
• f) disposing of the container assembly after the pre-filled liquid beverage is emptied from the container assembly.