This paper explores the use of the Flash technique in the treatment of extreme trauma in Dissociative Identity Disorder (DID) from satanic ritual abuse. The results include desensitization of trauma memories and the planned fusion of parts. I share my insights on safe application of the technique and modifications that can be used for highly fragmented DID clients and other complex trauma presentations. Strategies include ways to safely assess the severity of the memory, modifications in the Subjective Units of Distress (SUDS) measurement, instructions in applying the technique, modes of bilateral stimulation and use of the conference room technique. Nine case sessions are documented demonstrating nine variations in use of the technique. I describe how to install an engaging activity in parts that cannot come up with a resource. Additionally, I write about the use of playful extra resourcing to strengthen the engaging activity, leading to “boosting” of the Flash therapy session and hence faster processing of trauma memories. I hope that colleagues working in the field of trauma and dissociation can find the tools and strategies in this paper helpful for their professional development and also for treatment of their clients.