The way my T provided the alternating stimulation was with these two little gizmos connected by wires to a box that made them vibrate. He said I could put these gizmos under my thighs (one per side) or under my feet (in my shoes). I tried it both ways and liked under my feet better. I could feel the vibrations better that way. I controlled the tempo and the strength of the vibrations by twisting dials on the control box. That way I could get it just right for me. I admit, it sounds strange! But I found the rhythm of the vibrations quite soothing. If they were too strong and distracting, I would just turn them down. I always wore clogs on therapy days just in case we did EMDR so I could easily slip the gizmos under my feet.