Acupressure has been used in traditional Chinese medicine for centuries, particularly for pain relief. Research has shown that there may be a relationship between acupressure and sciatic pain relief, but studies are limited. However, the science we do have points to general pain relief from acupressure mats, and I have found it personally to be a godsend.
I have alternated between laying (with bare skin) on the mat included in the Yogi Bare Acupressure Set ($55) and using the lumbar pillow under the small of my back to target the area around the sciatic nerve in the lumbar spine. A few minutes on the pillow, and I get a reprieve from pain.