Abstract: A drink container piercing device for preparing a drink container with a cap to accept a drinking straw, the device having a device body adapted to be held in a user's hand, and a piercing assembly with a central projection and an arcuate blade. The piercing assembly is adapted to pierce the cap and create circular aperture via rotational cutting by the arcuate blade centered around the central projection. The arcuate blade produces a circular cut portion from the cap, which is removed to reveal a circular aperture for accepting the drinking straw. The cut portion is retained by the central projection, preventing the cut portion from falling into the container. The piercing assembly is retractable to prevent accidental contact with the arcuate blade, and the device body has finger projections to allow the user to stabilize the device when in use.