This paper identifies key themes of expressive interaction for VJs. VJs are visual artists who use digital media to express themselves to an audience during a live audio-visual performance. Those designing for the expressive use of technology can gain insight from an articulation of expressive interaction from the perspective of VJ practice. This is developed using a novel qualitative methodology designed to be sensitive to the subtle and tacit nature of expression. We detail our methodology, present the results of its application to a group of VJs and conclude with a discussion of the implications our findings may have for those wishing to design for VJs, or those in related domains that involve expressive interaction with technology.