Within social science research the complex nature of relationship-making and 'friendship as method' has gained enthusiasm. However, there is still a significant lack of research on 'friendship as method' with children and young people in participatory studies. Drawing on empirical case studies, we ask: how does 'friendship as method' work in research with children? The paper considers the role of vulnerability and reservations, friendship facilitator, and discusses the ethical dimensions of creating and sustaining 'friendships' between researcher and participants (as co-researchers). We argue that friendships in research are not a hierarchical or linear continuum, but a spectrum: friendships often mean different things to different people at different times; they can be positive and negative, both liberating and restrictive, fleeting and sustained, energising and tiresome. We recommend that participatory research with children considers not only the participatory components of power and action, but the emotionality and relationality of participatory research with children.