Doctoral supervision is inherently asymmetrical, and research advocates for more informal supervision practices with less power distance. Humour can make doctoral supervision more informal; however, this qualitative study demonstrates that informal humour does not necessarily foster less hierarchical relationships. We used video-recorded data from a meeting between two male supervisors and a female PhD student to explore how power structures in supervision are negotiated at the micro level. Analytically, we employed the novel technique of 'slow reading',  focusing on the effect each form of interaction had on the conversation. Our analysis revealed that although the supervisors aimed for informality, the jokes within the conversation did not eliminate power dynamics. While humour allowed participants to break norms and taboos, their ability to use humour varied depending on their power position. Rather than dissolving power structures, humour can obscure and conceal power dynamics and, in our case, even reinforce problematic gender roles.