I wouldn't "lube" the necks, per se. But you can try some mica to help. I have a nylon brush I would sprinkle some mica on or run the brush inside the mica and push the brush inside the case necks before seating. I only did this on some rounds that the necks were very thick or had a very tight bullet seat. If it's fired brass, it shouldn't be that difficult to seat if you cleaned the brass with corn cob or walnut. If you use Stainless steel, then it CAN make it more firm. It also depends on what cleaning solvent and additives are used in the solution. But I wouldn't lube the necks, as it can change up your seating consistencies, and maybe contaminate the powder.