Dracula Cards only give the extra experience to the wearer.
Lets say that a monster gives 100 experience.
That 100 gets split 50/50 because of the share exp. feature.
Now, I am being leeched, and I wear a quad drac weapon, the quad drac increases exp gained by 15% each drac, so quad = 60%.
5 * .6 = 3; meaning that now you add 30% more, and your exp becomes 50/80 points. If you throw in a shoe exp card that gives 10%, you'd get 3.5, add it to the 50 and that = 85 points.
If the leecher wears it, well he's just getting the extra exp for himself.
(By the way, if that explanation of how the dracs work was wrong, please let me know)