This paper examines how online interactions enable French teenagers to experiment with body performances that they would not feel comfortable exploring within the constraints of schoolyard social control. Drawing on data collected for a PhD study on pupils' negative reputations, this article presents a three-year survey conducted in four middle schools located in diverse socio-geographical configurations in the Parisian region. Using a combination of observation and interviews with students at school, as well as following a hundred volunteers' students on Instagram and Snapchat, this study highlights how the educational institution imposes differentiated control over bodies based on gender. Subsequently, the article reveals how teenagers use online social media to experiment with gender identities away from the watchful gaze of peers and adults. Finally, it analyzes some cases where the social control seeps into the intimacy of online exchanges and triggers shaming.