A drinking mug includes a lid affixed at the mouth of the mug. The lid includes fluid openings between a bottom portion of the lid and sidewalls of the lid about the circumference of the lid to permit drinking from any position along the circumference. The lid has a gasket that seals the mug closed when the lid is threaded to a closed position. When the lid is partially unscrewed, the gasket opens, permitting liquid to be consumed from the beverage container through the fluid openings in the lid. The lid includes a ramp-shaped cam and the mug includes a pivotable latch that engages the cam that prevents the lid from being unscrewed from the mug. The latch has a push button that releases the latch from the cam to permit removal of the lid.