Virtual environments are emerging as a tool for providing psychede-lic experiences due to the increasing interest in altered states of consciousness (ASCs) and the spread of VR headsets. However, the user experience of commercial psychedelic VR applications has not yet been adequately explored in HCI. To fill this gap, we conducted a user experience study of Cosmic Flow, one of the psychedelic VR available on Steam. In this exploratory study, six participants experienced Cosmic Flow and got interviewed. Analysis of user interviews revealed three main themes that articulate different aspects of the experience: moderate interaction, reflections on personal experience, and VR ergonomics. In the discussion, we derive seven design considerations to guide the development of psychedelic VR: non-active engagement, positive indolence and idleness, non-invasive multi-sensory modalities, creative and introspective activities, effects of priming, virtual nature, and comfortableness. The study contributes to design researchers and practitioners working on related experiences.