Despite the importance of the school-based practicum experience in teacher education programs, only limited research has investigated how supervising and pre-service teacher roles and relationships are interactively achieved in situ. Using conversation analysis, we interrogate extracts of practicum talk between supervising teachers (STs) and their pre-service teachers (PTs), revealing that asymmetrical relationships are talked into being within and through their conversations about classroom practice. We compare the different structural conversational arrangements that are employed when STs provide either positive feedback or raise issues of potential difficulty in relation to their PTs' observed classroom activities. Analysis reveals that STs tend to make evaluative statements when providing positive feedback, in contrast to initiating a process of critical reflection when talking about the need for improvements in PTs' pedagogic practices. We conclude by arguing the need for STs to instigate sustained critical and collaborative professional conversations with their PTs during the practicum experience, enabling them to engage in reflective practice and providing them with opportunities to extend their professional knowledge and skills, thereby potentially improving their future classroom practices.