How would I print coordinates in an item's description?

I'm working on an item for my mod that, when right clicked, shows a block's coordinates when it's used on them. I want to save these coordinates to the item's description when the player is crouching; how would I do so? I've got it printing coordinates in the action bar right now, but I also want it to set the item's description (referred to as "special information" by MCreator) to the coordinates if the player is crouching.