While shared personal experiences are a valued prerequisite of the peer supporter-service-user relationship, they have the potential to create harm. There are challenges in peer supporters being emotionally ready to hear the experiences of others, and how much personal information peers should disclose. As part of an international study that aimed to explore how peer supporters who worked in a neonatal context (providing support to parents whose infant(s) has received neonatal care) were trained and supported, new insights emerged into how peers' personal stories were used and modified to instil boundaries in peer support services. In this paper, we report on a secondary analysis of the data to describe how peer supporters' stories were valued, used, assessed and moderated in neonatal peer support services; to safeguard and promote positive outcomes for peers and parents. Following University ethics approval, a mixed-methods study comprising online surveys and follow-up interviews was undertaken. Surveys were distributed through existing contacts and via social media. Thirty-one managers/coordinators/trainers and 77 peer supporters completed the survey from 48 peer support services in 16 different countries, and 26 interviews were held with 27 survey respondents. Three themes describe variations in the types of stories that were preferred and when peers were perceived to be 'ready' to share them; the different means by which sharing personal accounts was encouraged and used to assess peer readiness; and the methods used to instil (and assess) boundaries in the stories the peers shared. In neonatal-related peer support provision, the expected use of peer supporters' stories resonates with the 'use of self' canon in social work practice. Peer supporters were expected to modify personal stories to ensure that service-user (parents) needs were primary, the information was beneficial, and harm was minimised. Further work to build resilience and emotional intelligence in peer supporters is needed.