A plug-in weight-shifting module that can be inserted into a variety of objects is presented. The module is equipped with a movable weight inside its body. Three-dimensional weight shifts are presented by controlling one-dimensional translational and two-dimensional rotational movements. To explore the use case of this weight-shifting module, eight weight shift patterns expressing certain emotions were created through a workshop and a qualitative analysis. User tests, to which three different embodiments and scenarios were applied, examined the following three cases: the weight shift patterns were presented to the user by a) a stuffed toy-style robot that mediated human messaging, b) a cushion that made the user relax, and c) a container that enhanced the user's movie-watching experience. User interviews revealed the feasibility of the module and its weight shift patterns for the user's perception of emotions.