How is Kool-Aid used as a visual cue to create contrast for an off-airport landing?
Kool-Aid is usually brightly colored due to added dye. It comes in powdered form, and you would normally add water to make a solution. 

If you have some in your aircraft in a suitable container (perhaps a paper bag), you can drop it on the ground during an overflight of an off-airport landing location. Hopefully the bag will burst on impact. When you return for an actual landing, the brightly colored powder can be a useful visual reference. This is especially important for landing with undistinguished surface cover such as snow.

Doing this successfully will take some practice, because you have to drop the right amount, in such a way that it breaks and spreads on the ground, at a suitable location, from some height that maintains your margins of safety. And if you're doing an off-airport landing in the first place, you probably have some other emergency going on at the same time.