In this chapter, we consider our symbiotic relationships with our gut microbiome and how these relationships are increasingly serving as a site for experimental design. We briefly overview existing work at the intersection of design and microbes, then turn to our case: the Shit! project, an inquiry into the methodological challenges of designing with microbes. Through experimental activities, such as gut drawings, performing the inner workings of the gastrointestinal tract and fashioning probiotic cakes with the semblance of one’s fæces, we consider material and collaborative explorations of human-microbe relationships, and what it might engender to invite participants to engage with themselves as multi-species events; as part of the planetary ecosystem. This engagement personifies, through practice with others, an embodied engagement with the materiality of what is at stake. The Shit! project embodies an evolving inquiry into the role of method in opening up new spaces for design, and exemplifies an emerging approach to more-than-human design in practice.