I use a vibrating seat cover which massages a total of 6 areas, 4 areas of your back, 2 bum and 2 upper thighs.
Each is individually selectable and has 6 various modes like random, sequential, etc.
It is sensational, as I travel up to 10 hours in a car and works great in cessna twins... needs a 12v supply.
PM me if you want details...