"If you want to sell a guest a particular brand of liquor, nod your head slowly as you mention the brand. For extra effect, repeat the brand at the beginning and end of the list of brands you recite, e.g. "Well, we have Absolut (nod), Brands X, Y, Z, Q and R, and Absolut (nods again)".
This technique is called the Sullivan Nod and it works about 90% of the time - and no, nobody ever notices when you're doing it."
I have found it helpful to do the stretching exercises my physical therapist recommends. Do some core strengthening exercises, such as the ones highlighted at The Mayo Clinic. By keeping your core strong, your back won't put itself in a position to cause that sciatica pain you are having.