This article introduces the idea of ‘affective coding’ as a form of affectively loaded, digital social steganography – a form of hiding messages – as it presents findings from interviews with new fathers struggling to cope with and disclose mental illnesses, against the context of cultures of silencing. While previous expositions of online social steganography have considered its role in privacy management or its employment in concealing identities, we conceptualise affective coding as an agentic and discursive-material digital practice of attempted revelation, occupying a liminal space between silence and more explicit attempts to reach out, disclose and seek support. Our findings show men undertaking a range of seemingly minor online acts, each demonstrating subtle strategies of managing self-disclosure and social media architecture, and each encoded with a substantial amount of affective investment. We discuss motivations, strategies and outcomes of affective coding, before discussing its significance for self-disclosure in platform societies.