In Chinese Internet spaces, "fishing" is a form of non-literal communication that tries to lure or bait others. We conducted a case study of fishing on a Chinese Q&A platform in which we deconstructed the linguistic structure of the fishing language and identified its features by employing analysis techniques informed by Critical Discourse Analysis (CDA). Additionally, we examined the relationship between fishing practices and the specifics of the underlying communication platform. We found that fishing can be characterized as a reaction to rigid norms of politeness and friendliness imposed on users by platform owners. Our analysis reveals that fishing is organically connected with other social interaction within the community and facilitates autonomous and active negotiation of boundaries and linguistic norms for online discussion of controversial topics. We challenge the characterization of non-literal communication as "abnormal," and contribute a more refined understanding of online linguistic norms, community cohesion, and civil engagement.