Gender pluralism has become a rich scholarly topic in Southeast Asia, especially with the rise of LGBT mobilisations across the region in the past decade. Transgender ritual specialists dominate the field of study, with a growing body of literature on Southeast Asian queer expressive cultures. However, queer performances in several classical performing arts are often excluded from the scholarship due to the field's association with the “traditional”. In this article, I address this scholarly gap by examining the social lives of queer men in Thai classical string music. I focus on a strategy called kep aakaan or “keeping condition” in which the musicians in question carefully articulate and disarticulate their femininity to render their gender nonconformity ambiguous under the heteronormative gaze. Using ethnographic methods to investigate the lived experience of queer male musicians on and off the stage, I show that “keeping condition” is not just about managing the display of queer potential but is also closely intertwined with morality and citizenship. Drawing on the ideas of tacit subjects and contextual sensitivities, I argue that “keeping condition” exposes the fluidity in which queer musicking bodies move between queerness and heteronormativity in ways that are more reconciliatory than confrontational. By focusing on the complicities of queerness and heteronormativity, I argue that non-normative classical performing arts can be a productive site for critical gender, sexuality, and queer studies in Southeast Asia, cutting through the “traditional” and “modern” divide that looms large in the region.