Enemies in most dungeons hit like wet noodles and have no mechanics other than "don't stand in orange". You can probably pull more than you think! Plus if you want to improve, there's no better way than by doing. I didn't start actually feeling comfortable on tank until I got the knack for wall-to-wall pulls myself.

Don't be afraid to ask them to slow down or initiate a vote kick if they're really asinine though. Pulling for the tank is a jerk move unless the tank has agreed to it.