A cap assembly comprises a base portion, a head portion, a fluid conduit, and an engagement member. The base portion is configured for removably coupling to a neck of a fluid compartment of a drinking vessel and includes an aperture in fluid communication with an internal volume of the fluid compartment via an opening at the neck. The head portion is rotatably coupled to the base portion. The fluid conduit is operably coupled between the aperture at the base portion and an outlet at an upper end of the head portion to enable a fluid to flow therebetween. The an engagement member is mounted to the head portion and shaped to engage a compressible portion of the fluid conduit. The head portion is configured to rotate about a longitudinal axis relative to the base portion in a first direction and in a second direction, opposite to the first direction.