Portuguese language students in the United States typically also speak Spanish, and Portuguese programs, influenced by ideologies of linguistic purism, ceaselessly battle against its interference. This article describes a qualitative study of the treatment of Spanish utterances--called "taquitos" by participants--in a beginner-level Portuguese class. It presents the classroom as a space of language socialization where students are apprenticed into a culture of strict language separation that demonstrates our field's monolingual bias. Microanalysis of videorecorded classes shows how error correction practices socialize students into upholding monolingual immersion through constant vigilance and mobilization against "taquitos." Gaze, body orientation, and gestures as attention markers reveal a "taquito" hot seat that marginalizes and places Spanish-speaking students in intense negative focus for not producing Portuguese in "uncontaminated" forms. Given the harm such practices may cause, the article urges the field to examine our rigid insistence upon artificial classroom monolingual immersion and promote flexible, strategic translanguaging for more effective world language pedagogy.