I noticed that if I have a pintle hitch in the receiver of my F150, generally no one tailgates me. So I decided to do an experiment with the old Protege. It seems in this car every one tailgates the living daylights out of me regardless of speed when driving this car. It has a 1 1/4" receiver. I put a 1 1/4" - 2" adapter I use for the bicycle carrier, then put the pintle hitch in for a couple of days. Amazingly, this hideous lump of metal deterred most people from tailgating me. I know in many states, It's illegal to have hitches in receivers when not towing. My state is not one of those states, so no law was broken.
As to how I deal with tailgaters, I try to yield to them as safely and as quickly as possible. I do not know whats going on in the tailgaters life, their level of sanity or sobriety, nor do I know how heavily armed they are. I also never obviously turn my head toward them as they pass. The less interaction, the better.