A lid assembly including a camming lever and a sealing member for selectively sealing and unsealing a drinking aperture of a lid main body. The camming lever is rotatably to selectively move the sealing member between a sealed position adjacent to and an unsealed position spaced apart from the drinking aperture. The camming lever includes a lever arm extending from two cams having a cam axle extending therebetween. The cam axle is pivotally attached to the sealing member, which is pivotally attached to the lid main body. The cams engage an upper surface of the lid main body. A stub axle extends laterally outward from each cam and engages a ledge which limiting upward movement of the cams.