Psychedelic assisted therapy comprises three stages: Preparation, Psychedelic Session, and Integration. Preparation is key for maximising the potential of a beneficial psychedelic experience and integration is important for prolonging improvements. The psychological flexibility model (PFM) appears to be a promising one to guide psychedelic preparation and integration. This paper proposes a model that utilises the PFM as informed by a previously published qualitative study of patient accounts of change processes in psilocybin therapy that identified themes of acceptance and connection as associated with positive outcomes. This new model, the ACE (Accept, Connect, Embody) model presents the six psychological flexibility processes, renamed and rearranged in an acceptance triad (defusion, present moment focus, willingness) and a connection triad (self as context, values, committed action). This paper describes the ACE model and how it is being used in an ongoing trial of psilocybin treatment for major depression. It also describes qualitative evidence supportive of the idea that psychological flexibility may be key to characterizing the processes of change involved in psilocybin assisted therapy for depression. These and other results suggest that psilocybin may be specifically increasing psychological flexibility and point to the possibility that psychotherapy approaches incorporating the PFM may serve as a means to deepen and extend the benefits of psilocybin treatment, thus bridging the experiential gap between a potent inner experience and an outer life better lived.