This paper discusses the relationship of swearing and slang to code-switching based on data obtained in a Basque–Spanish language contact situation. The study is based on 22 hours of recorded material of 22 Basque bilinguals, both L1 and L2 Basque speakers. In Greater Bilbao, even the bilinguals who do not frequently code-switch shift to Spanish to introduce slang or swear words to otherwise Basque discourse. The susceptibility of these elements to switching is examined from structural, discursive and sociolinguistic points of view. The phenomena are understood to strengthen one another: when different stylistic and stance-taking devices co-occur, they become even more salient, thus underlining the effect for which they were introduced to the conversation.