Previous studies of educational translanguaging have described it as an instructional and inclusive practice supporting the active classroom participation of students from diverse linguistic backgrounds. This chapter demonstrates how in monolingually-oriented educational contexts, translanguaging can also constitute a form of subversive language play targeting the local monolingual norm. The data are video-recorded lessons from secondary-level CLIL (Content-and-Language-Integrated-Learning) classrooms in Finland. In CLIL classrooms L2 is often upheld as a normatively assigned medium of interaction, particularly in whole-class talk, and students use their shared L1 in peer interaction. This chapter offers a case study investigating how one student's translanguaging, which takes place as a reaction to the teacher's enforcement of the L2-only norm, is treated as a 'language mix' by other participants in the classroom. Drawing on conversation analytic (CA) methodology, we describe the sequential unfolding and the normative context of the focal student's translanguaging, as well as practices of categorisation with which other students respond to him. We suggest that these kinds of situations can help to empirically tease apart some differences between translanguaging and code-switching. Further, we argue that the 'meaning' of translanguaging to participants cannot be established without considering its relation to locally upheld norms around language choice, which in the present case are employed as resources for the construction of language play and subversive identities.