The trick is to wear a set of goggles, and a thick coat, GI issue works well. Then, you light the bottle rocket, and wait until just before it ignites the rocket, and throw it at your target. In mid flight, the rocket ignites, and shoots off in the direction it was already going. The impact on your buddy's chest is spectacular!
Caught one one time in my pocket, where the fire crackers were. It was quick and painful!