Wool string is used to hang items for Smoking. To place it, just use Right Click.
Multiblock
A piece of string above a firepit.
Smoking is used to preserve Meat and Cheese. To smoke meat, it must have first been Brined by sealing it in a Barrel with Brine. You may also salt it first. Cheese does not have this requirement.
To start the smoking process, add the item to the string above a firepit. The firepit must be within four blocks, directly underneath the string. The string should begin to generate some smoke if it is working. It is important to note that the firepit must only be burned with Logs. Using something like Peat will instantly give your food the Disgusting trait!
The smoking process takes 8 in-game hours. Happy smoking!