Well weapon stacking in my experience only requires you to put items into the stacks and then enjoy....
It is really simple,
1) Empty the slot you want to put the item into.
2) Go to ANY vendor with a bag in the LAST bag slot.
3) This bag must be empty and have ATLEAST 14 slots.
4) DRAG an item from the vendor into any of the first 14 slots of the bag and if you get the right bag slot it puts it in the empty slot of your character.
Here is a picture I saved from another article from elitepvpers (THANKS TO THE OWNER)
(I FORGOT THEIR NAME...SOZ)
1) Make a hunter.
2) Fill ALL the slots possible (some are buggy and don't ALWAYS work, in my experience)
3) Use chance on hit items only.
4) Use steady shot on something.
5) If done properly you might notice that you hit something in the 2 million mark.
6) Don't get caught but go into an instance or pvp area and try it out.
7) Target noobs who won't understand why you hit so high.
8) Be careful because I have seen some ask in chat if it is normal that they just died from an overkill of about 1 900 000 damage, if they ask around you should either:
A) Whisper them and let them know you have special gear for donating to the server or something.
B) Delete items or log off (/logout then /console logout for instant logout) and delete character.
You can try making a new account and using that to take extreme measures if not being banned is of severe importance to you.
Hide the fact you are slot hacking or weapon stacking by putting robes in shirt slots and such, this is less likely to get you caught...