The safe & proper thing for you to do in this situation is to further increase the distance between you and the car in front of you. The guy behind you gets the opposite of what he intended, and fuck him too. People who tailgate are scum.

When I'm feeling wicked, I'll do an imitation of someone who's lost, and randomly put on my left blinker and slow down. If the tailgater is the type who just does it habitually without thinking about it, that's often enough to get them to leave some distance.