We examined uncomfortable moments that damaged rapport during group interactions between college students in training to become speech-language pathologists and adults with traumatic brain injury. The students worked as staff in a community-based program affiliated with a university training program that functioned as a recreational gathering place for any adult with traumatic brain injury who wished to attend. Analysis revealed the interactional difficulties experienced by the student staff as they tried to manage offensive humor produced by an individual with traumatic brain injury without interfering with rapport. Nevertheless, successive instances of sexually explicit humor resulted in rapport being damaged to such an extent that it eventually derailed the entire interaction. Results are discussed in terms of those aspects of context outside the communicative intentions of any of the interactants that contributed to this breach in rapport.