Sexuality-assemblages emphasize a relational more-than-human approach to conceptualizing the becoming of sexuality. This article brings together Fine’s notion of “working the hyphen” with a new materialist ontology of sexuality, to explore the space and form of the hyphen within the sexuality-assemblage. In “working” the sexuality-assemblage hyphen, I explore the onto-epistemological space it inhabits, who or what is implicated at this material and metaphorical juncture, and how this shapes the production of knowledge about sexuality. More than a simple connecting device between words, the hyphen is conceptualized as a metonym for the dynamic space in-between assembled elements. The hyphen-space is generative and capacious, enacting important onto-epistemological understandings about research(er) “objectivity,” response-ability and ethics integral to a new materialist becoming of sexualities research. More broadly, I consider how a new materialist ontology shapes the form of the hyphen itself, elaborating the view that even the smallest of marks can matter.