What is the Dragonfire Perk and how do I use it?

I haven't had the game long and have only been playing online multiplayer so far. I just earned the Dragonfire scorestreak perk but I dont know how to use it. Everytime I tried with the conventional method of pressing right on the d-pad, it just kept saying that I couldn't use that here. I tried it inside, outside, against the floor, against a wall, against a vehicle... nothing!

Anybody know how I am supposed to use it?