There is a growing literature that seeks to explore what is 'sensitive' about 'sensitive' research. In order to problematise and interrogate the concept of what may or may not be considered 'sensitive' research, this paper draws on four related projects exploring sex, intimacy and relationships for young people, over 16 years, who have life-limiting or life-threatening conditions (LLTCs). The authors focus on how, when and why these projects are regarded as 'sensitive' and consider who defines them as such. Drawing on the notion of methodological performativity, a mixture of complex phenomena that explores the relational aspects in interprofessional team practices, the authors examine aspects of the process of doing 'sensitive' research, exploring how research methods and techniques are employed because the research has already been defined (by others and the authors) as 'sensitive,' while simultaneously serving to (re)construct and (re)enforce the 'sensitive' nature of it.