I put on the hazards...until they back off. Otherwise they stay on until I change lanes ...when I feel like doing so or if I am in the left lane and right lane opens up. If they dont back off.
I've noticed at the very least the hazards irritate them ..for me its more for safety purposes: they are noticing my vehicle moreso than just any other of the other 419090 cars they tailgate everyday... if I have to slam the brakes for whatever reason...they're focusing on my car because of the hazards.
No adjusting of speed either, unless I feel like doing so .. I usually maintain same speed on cruise control anyway. Other folks live by braking on their tailgaters but I think that's way inefficient ...delaying themselves and wasting brakepad..