This article explores the mobile and material dimensions of a writing practice we call pocket writing. Emergent in our 6-year ethnographic fieldwork at a public high school, this practice involved adolescents composing and carrying their self-sponsored writing close to their bodies. We consider the pocket both a physical artifact--the place from which writing emerged at the right moment--and a metaphor describing how youth created small, portable boundaries around their writing to facilitate its invisibility and mobility. Using a transliteracies lens, we worked alongside youth to trace the circulatory pathways such writing took relative to the official institution of school. These high school students made agentive rhetorical choices, sometimes deliberately disconnecting their writing from school as an everyday resistance practice--an effort to keep school in its place. In theorizing pocket writing as a mobile and embodied extension of writing (for) the self, we argue its "pocketed" nature is key to its transformative power.