"Seat massagers" refer to devices that are built into seats (such as car seats or office chairs) and are designed to provide massages to the person sitting on them. Full definition
Most of the extra space goes to the rear seats, which gain 4.2 inches of legroom and a slew of optional features — climate controls and seat massagers for the outboard passengers, a mini refrigerator and more. (cars.com)
The kids, spoiled as they are, noted that there was no rear - seat entertainment system nor any second - row seat massagers («When I was your age we had vinyl bench seats and no seatbelts! (autoweek.com)
Standard features introduced for this model year included soft - close doors, an enhanced seat massager, and additional soft - touch materials on the dash and door. (ftmyersjaguar.com)