Twenty-seven semi-guided office hours’ consultations between lecturers and Spanish-speaking undergraduate students were recorded at five different universities in Europe where English is the medium of instruction. The linguistic data gathered show that metaphor plays a significant role in the way that lecturers explain to visiting Erasmus students how assignments, exams or course contents should be approached and understood. When mentoring their students, lecturers often frame the advice they are giving in metaphorical ways; occasionally this is done overtly, through establishing analogies or non-literal comparisons, but more often it is done covertly, through the use of conventional metaphorical expressions that are not accompanied by words or phrases that signal that the lecturers’ words should be understood as metaphors. This article examines extracts of talk from 5 academic conversations, looking at the different ways that ideas are framed metaphorically and the kind of responses they provoke in a conversational partner. The initial hypothesis was that overt metaphors would be a particularly effective means of communicating an idea in these cross-cultural mentoring sessions. However, when we compare this with covert uses of metaphor in the corpus, there is only weak evidence that it is so. Rather, the communicative success of any use of metaphor seems to depend very largely on the way that the conversational partners enact their roles as collaborative partners in an academic conversation.