"Improvisational theater" is a collaborative art form in which performers co-construct unscripted narratives, often based on audience suggestions, and always guided by a set of central principles. One practice common in improv instructional settings is "side-coaching," the move of providing immediate, public, verbal feedback during a rehearsal. One of the pioneers of improv, Viola Spolin, conceptualized side-coaching as an essential component of any theater exercise, and she encouraged teachers to use side-coaching during warm-up activities, games, and scene structures to orient improvisers to particular aspects of practice (e.g., "Share your voice with the audience!"). Similarly, the author sees side-coaching as a key practice in developing students' speaking and listening skills, and she uses side-coaching to provide feedback to students during whole-class discussions of texts. In this article, the author reviews the connections between improvising and leading discussion, as well as what is known about side-coaching as an instructional practice. The author then describes how the principles of improv and Spolin's notion of side-coaching shape how she leads whole-class discussions.