The issue of “expertise,” while not always termed as such, has long sat at the center of much trans theory. Initially held only by medical authorities, transgender expertise has shifted alongside changes in cultural attitudes and diagnosis models: transgender individuals now often find themselves conversationally positioned as “expert” on the phenomenological experience of being transgender — even if they do not willingly take on that social role. This article considers, first, the role of the trans speaker as expert, and second, the use of expert discourse or expertness (Nguyen 2006) by trans male video bloggers (vloggers) on YouTube. As highly public individuals, these vloggers strategically assume the expert role to correct viewer “misbehavior.” In their talk, vloggers utilize a specific mode of recipient design, advice-giving, to focus attention on viewers’ lack of knowledge and away from the vlogger’s subjective experience. If successful, their talk forecloses on the possibility of further viewer challenges.