The idea is to find an area that is tense, and then purposefully tense it more until it naturally lets go. It may be that you are stopping yourself before this natural reset happens, or it could be your system simply does not feel safe enough yet to let go of it’s tension. Some one-on-one work with a good Somatic Experiencing Practitioner might be helpful for this, especially with someone also trained in Somatic Practice, the work of Kathy Kain.