Here is an electric scalp massager that you can use on your head to relax. As it turns out, it is also great for cats. The device is rechargeable and has 3 nodes to treat your head. It has a button on top to change speed. You can also hold it to turn off the massager.
As you can see in the above video, not all cats like this massager. It takes them sometime getting used to. You will also want to regularly clean this to get all the hair out.