This paper describes the research approach of a case study ethnography. The study sought to explore the peer group understandings of five male friends aged between six and eight years. In exploring the social dynamics of peer culture, and in particular how these dynamics interacted to define, regulate and maintain particular understandings of masculinity, the study's research approach drew on Mackay's (1993) affinity group method. This method of grouping people of similar interest and engaging them in discussion aims to promote a sense of group cohesion, which encourages the participants to speak with openness about their ideas, interpretations and feelings (Hickey & Fitzclarence, 2000). The intimate and informal context facilitates the identification of shared and contradicting stories, ideas and understandings through clarifications, negotiations and confirmations. Within a description of the study's methodological framework, this paper outlines how this approach was adopted and modified for young children. The affinity group approach is presented as useful in exploring the social dynamics, relevances, complexities and subtleties of peer culture.