Creativity training has been generally based on avoiding critique during idea generation, although benefits of argumentation have been shown during idea selection and elaboration. The research reported here aims to understand how argumentative interactions involving role-play, with subsequent group reflection on them, contribute to collaborative creative design projects. The study was carried within a specialised Masters course at the Royal College of Art (London), organised jointly with Imperial College London, and focuses on analysing group reflection sessions of two groups of students whose on-going project was initially defined as “communication by touch”. Results showed that although students reported difficulties in playing argumentative roles that were not aligned with their personal views, their debates enabled them to arrive at “Eureka!” moments with respect to better grounded and precise definitions of their project concepts. We highlight the complex ways in which emotions circulate with respect to “Eureka!” moments, role-play and grounding. Given differences in ways that groups played out their assigned argumentative roles, we conclude that role play debate and group reflection on it need to be applied and considered as a whole in creative design training.