This paper engages with Kathleen Lubey’s concept of the “grammar of eroticism” in amatory fiction and develops a theory of em dash usage in Eliza Haywood’s Fantomina (1725). Arguing that Haywood innovates the amatory convention of the em dash in the novella, the em dash is read as a visual cue that signals conversation. By marking conversation with the em dash, Haywood directs the reader to closely examine the conversations that occur. This usage of the amatory convention allows analysis of conversation as reciprocal or non-reciprocal engagement. The well-established metaphor of spoken conversation representing sexual conversation enables the em dash to introduce verbal and sexual speech and depict consent; conspicuously, there is no reciprocating em dash during Fantomina and Beauplaisir’s initial sexual encounter. Engaging with these models of conversation is instructive for the reader, and after exploring failed models of conversation, Haywood presents an ideal model that reveals how to responsibly navigate amatory language.