@popolopo This is an interesting topic, but I have no idea what to do for sciatica. I had a bout of it in the summer and despite hearing that sitting for long periods of time was not good for it, I did that. We drove 3 hours up and 3 hours back to our place in Maine, and then sat around for about 2 hours talking to my husband's adult grandchildren who were there. The next day the pain was so unbearable, it was honestly worse than childbirth. It caused me to have a presyncope episode, fall to the floor, and have a femur fracture! That led me to discover that I had somewhat advanced osteoporosis, and the rest is history. Not a fun journey.
So although I can't say what you should do for it, I can say, do not sit for very long periods of time. I am interested in hearing what others say helps it though. Interestingly, after fracturing my femur, my sciatica went away! That was the only time I have ever had it except for having it mildly when I was pregnant, many, many years ago.