Consociational democracy, as a political project of passive coexistence and agreement among ethnic elites, has been shaping sociopolitical processes in the world's postconflict regions, including Northern Ireland, Lebanon, and Bosnia and Herzegovina (BiH). In BiH, this political model, when combined with continuous governance by the International Community, solidifies war-generated ethnic segregation and erodes state sovereignty. Furthermore, these political, social, and spatial arrangements lead to the institutionalized separation of ethnic groups and territories in BiH. At the famous Mostar Gymnasium, my primary research site, this is manifested in the simultaneous unification of the school management and segregation of classroom spaces, classroom instruction, and students along the ethnic lines. The implementation of a top-down cartography of peace building at the school led to the destruction of common spaces for students to interact. This spatial ethnic division limited what the students call, in the local vernacular, miješanje (mixing). I understand mixing as a long-standing cultural practice of interconnectedness and intermingling among ethnic groups. This article pays special attention to the practices of bathroom mixing at the school that unfolded alongside the consociational model of democracy and the history of mixing as an interethnic social order. Focusing on bathroom mixing illuminates the paradoxes and unintended effects of the spatial governmentality of peace-building in BiH.