Drawing upon long-term ethnographic research in Namibia, I examine the label ‘MSM’ through a materialist interpretation of affect, viewing ‘MSM’ as a ‘doing thing’ that unsettles the boundaries between subjects and objects. From this analytic perspective, I reconsider the ‘MSM’ label as an inadequate signifier that overlooks, conceals, or erases social complexity. Instead, this perspective reveals what happens when the MSM label travels, thereby better accounting for the socialities it is instrumental in making up. Its very design and appearance – which portray bodies and behaviours in universalistic ways – allow this ‘doing thing’ to gain entry to diverse spaces where it comes to exist alongside some contentious postcolonial political formations, such as those surrounding LGBT rights. I argue that although the label is designed to be insulated from politics, as a ‘neutral’ behavioural category, when ‘MSM’ travels it is still highly relational, continually entangling itself in contexts, stirring up postcolonial anxieties, and reinforcing global inequalities, while also setting the stage for global health worlds coming into being.