The use of toys as teaching aids in physics classrooms has a rich history, and the role of play in science education is a well-established line of research. Much of what has been written on the topic has included discussions of specific toys and the implications of using those toys to teach physics. One of the toys from my childhood that seems to be absent from discussions in this journal is what I call a "twirly whirly," though I have also heard it referred to using the names "button flywheel," "buzz toy," and "whirligig." In this paper, I will discuss the development of a 3D-printed twirly whirly, its use in an inquiry activity to introduce moment of inertia, and a few ideas for extending the activity into more robust physics investigations.