A fluid container and method of manufacture. The fluid container may be a drinking vessel, and may include an opening in a bottom surface thereof and a coupling device around the opening. The coupling device may include a first component in contact with the bottom surface of the fluid container around the opening and a second component in contact with the first component in a fluid-tight closed configuration. The second component may include a magnetic material. The coupling device may be biased in the fluid-tight closed configuration via magnetic attraction of the first and second components.