What are people in The Walking Dead really using to make it seem like they are rubbing Walker guts on themselves to stay hidden from Walkers?
Are they using like BBQ sauce or something?
It's usually a combination of liquid latex, fake blood and some other materials. Special Effects guru Tom Savini once used real pig intestines, but apparently the stench was so offensive he had to re-think his strategy. I've seen this description on a few sites:
Lay out multiple layers of liquid latex on a flat surface, like a glass or marble countertop, and then take a large amount of paper towels and roll them into a sort of makeshift rope before dragging them carefully through the liquid latex, pulling away from the surface. After that, soak them in some red liquid, and you'll have some really disgusting unreal guts to throw around.
The "red liquid" in question is probably fake blood. This is the recipe used in The Evil Dead:
Whip the creamer until it takes on a paste-like consistency, then stir it slowly with the Karo syrup. Stir in the food coloring, and you'll have yourself some excellent fake blood.