The “emotion curve” is a creative methodology that asks research participants to express in graphic form changes in their emotional responses over time, reflecting on a given time period or on a particular activity or event (in our case, music-based activities). This methodology was developed as part of our research with community music-making NGO Musicians Without Borders at their “Music Bridge” participatory music and movement training program in Derry/Londonderry, Northern Ireland. This article discusses how the “post-conflict” context of our research, and our engagement with the principles of prefiguration and participatory action research, shaped the development of this innovative methodology, paying particular attention to achieving methodological “fit” (or commensurability) with the practices, objectives, and ethos of our research partners. This creative and “fitting” (or commensurate) methodology has been the basis of a “mutually transformative dialog” with our research partners.