In this manuscript, we foreground the concept of critical affective theory drawing on scholarship from within and outside of literacy education and highlight testimony and critical witness as an example of affective practice to foster students' literacy experiences. Situated within a study of a writing methods course in an elementary teacher education program, we explore testimony and critical witness for its potential as a critical-affective practice that may support relational and justice aims within teacher education courses and school-partnerships. Drawing on video, interviews, and writing artifacts, we focus on two child/adult pairs to illustrate how affective practices were embedded in the literacy routines of work with children and how the critical-affective framework, as well as particular pedagogies and structures of the course, seemed to support teacher candidates to attune to particular moments with children in impactful ways. We also show how children responded to the intentional use of critical-affective pedagogies designed to center adult educators' vulnerability as invitation for children to serve as witnesses and, in the cases we discuss, how the novice teachers' modeling of risky and vulnerable writing functioned as an important invitation for students to do the same. We found that both the teacher and students contextualize their work as steeped in the affective and highlight the value of their relationship and the practice of collective risk-taking as central to their learning together. We conclude with hopes for the field's continued inquiries into the multiple ways we might envision the important intangibles of critical-affective literacies as "tangible" pedagogies in K-12 and teacher education classrooms.