Can I do just bilateral stimulation or eye movements without the therapy?

There are many kinds of activities that are bilateral stimulation—for example walking, running, bicycling, and drumming. Most people find these soothing, but they are not EMDR Therapy. EMDR Therapy is a precise protocol, which is designed to bring up the disturbing material in a systematic way and to reprocess it to an adaptive resolution—precisely what your brain has not been able to do on its own.