There is not really any way around it but get more gears yourself (Either HQ crafted gears or Duns drop gears). Another way as well is ask the pt knows upfront to watch their aggro meters just because , well. you are under-geared. And NEVER attempt a mass pull whilst under-geared yourself, not only you make a fool out of yourself for not be able to take hits and making your jobs MUCH MUCH harder by failing to hold aggro, but also you piss off the rest of the pt. Nothing upset people most but seeing an under-geared tank go on a mass pulls and die. Go slow and calm, let they know your gear are not great and you are still a leaner, you will be fine and they will be more than happy to cooperate.