"How to" guides and software training resources support the development of the skills and confidence needed to teach in virtual classrooms using web-conferencing software. However, these sources do not often reveal the subtleties of what it is like to be a facilitator in such an environment--what it feels like, what issues might emerge and what personal challenges will be faced. This paper reports findings from a phenomenological study guided by the following question: "how do experienced teachers describe and understand their experiences in synchronous virtual classrooms?" which aimed to find out what it is like to be a teacher in a virtual classroom. The transcripts of semi-structured interviews with four experienced web-conferencing users across the UK were analysed using interpretative phenomenological analysis. One of the themes that emerged--"facilitating in a demanding environment"--is explored in this paper to give an insight into participants' experiences and some of the challenges faced when encouraging interaction in an environment where feedback is limited. The discussion may be relevant to those developing their practice in virtual classrooms, as well as staff developers and software designers.