You cannot make yourself have a flashback, nor will you have one unless you are emotionally ready to remember something. Once remembered, the memory can help you to face more of the truth. You can then express your pent-up feelings about the memory and continue on your path to recovery. Think of the flashback as a clue to the next piece of work. No matter how painful, try to view it as a positive indication that you are now ready and willing to remember.