I made this vibrating ring stack by wedging the swim noodle inside a hole in a box. I pushed a small motor from a cheap electric tooth brush I found on Ebay inside so that it vibrates. The rings are cut from coffee can lids.
Unfortunately, I held the camera at a funny angle, and the blog does not accept a rotated picture.
This 2nd vibrating ring stack is made by using a small, very clean, brand new plunger with a round massager attached below it. It vibrates when the person pushes the rings (swimming noodle sections) onto it. Again he enjoyed the vibration. He has very good range and motor control in his right hand and I positioned his left hand to grasp the plunger near the bottom.