I've had the same problem for years. What works for me:
Immediately after it goes out, rest. Ice and ibuprofen the first day. Then heat after that. When it loosens up some, lie on the floor facedown. Get your hads next to you like you're going to do a pushup. Push up, but keep your hips on the floor. You want to raise your torso as high up as you can. This pushes the discs in your lower back into their normal position. When they bulge and press on nerves is what causes the pain. You have to kind of squish them back into shape so they stop pressing on the nerve.