You are on the wave and have the rights to surf the wave, so if someone drops in behind you, they should either cut away from you or go straight, to tail you is an aggressive move to intimidate you. What can you do? Nothing really, many boardies don't practice good surfing ettiquette, and you won't be changing anybody's mindset. I think that boardies get really frustrated when you catch a wave outside of the critical zone, and if you appear to be cruising, while the boardie wants to rip, it may be too much to resist. Just make sure that you are not hogging all the waves, and in the example, if you peal out off the shoulder and allow the boardie to take the wave, you score points at the break with other boardies that may be watching. They would rather hate you than have sympathy for you, so they will be very conflicted.