"SHTF" or "When shit hits the fan" is a popular phrase referring to the ultimate situation in which a man would need to try and survive off the land. The collapse of civilization.
The phrase is commonly used among survivalists and generally most firearm collectors or outdoors man.
See: apocalypse, end of the world, FUBAR, Survive
Guy 2: "Thanks. I'll probably use this in a SHTF situation.
Complete civil unrest, the end of the world as we know it. An event that the beaten, republican losers are praying for now that their party has has been marginalized.