The buttock muscles can carry a lot of tension and even contribute to lower back pain. Butt massage can range from Swedish massage techniques for overall relaxation to specific deep massage techniques to address pain and injury.
The largest buttock muscle is the gluteus maximus. Smaller muscles are the gluteus medius and gluteus minimus. Underneath this outer layer of muscles lies six smaller muscles called the deep lateral rotators. The piriformis is the largest of the deep lateral rotators and can cause sciatic pain when it presses on the sciatic nerve as it runs through the buttocks and down the legs.
You can massage the buttock muscles either while massaging the back or while massaging the back of the upper legs.