A drinking vessel having a cup with a removable lid having an inlet-outlet opening which receives an elastic straw-vent assembly having a flexible tubular straw and an air passageway forming a vent opening. A cover movably mounted on top of the lid, shiftable between a closed and an open position, with an inward surface of the cover forming fluid tight seal with the vent opening when the cover is in the closed position. In the closed position the cover engages the straw, folding the straw against the lid to seal the straw passageway, and in the open position, the straw fluid passageway and the vent opening are unobstructed by the cover. A removeable elastic straw-vent assembly is also disclosed having a tab to be grasped by the user for easy removal for cleaning.
