Undertaking infant-toddler practicum during initial teacher education is critical to ensuring preservice teachers (PSTs) are well prepared for their future role as early childhood teachers. PSTs, however, can face challenges in infant-toddler practicum given the demands of this unique teaching and learning context. A knowledgeable, experienced educator as a guide is key to supporting PSTs' learning during placement. This paper illuminates the practices of an infant-toddler educator who supported an international PST's learning during her first nappy change on an infant-toddler practicum in an early childhood service in Australia. The paper addresses the scarce literature on PSTs' experiences in infant-toddler settings, which can guide their relationships with colleagues. Drawing on the theory of practice architectures, we analyse a video vignette of the PST and educator during a nappy changing practice. We highlight the practices of both the educator and PST which helped the PST learn by being 'stirred in' to this common but unfamiliar practice for her and many other PSTs who may never have held a baby before. Implications call for cooperative and experienced educators who can support PSTs with pedagogical and practical elements of the practicum.