The Flash technique was developed by Philip Manfield (2017) as a way to decrease distress in traumatic memories. If you would like to get trained in Flash by its creator, please see:
Manfield, Philip & Lovett, Joan & Engel, Lewis & Manfield, David. (2017). Use of the Flash Technique in EMDR Therapy: Four Case Examples. Journal of EMDR Practice and Research.
Four Blinks Version of Flash: An Open Approach To Trauma Reprocessing 