ah...i seen in it before..in fact, i've done it before too....just light a wood chip and stick it in front of the nozzle, and you'll have a continuous stream.....your nozzle, though, might melt, and stop working after a while...but its still great fun....
we did it at a friends that lived in a gated community, so there was a lake in his backyard...we did it on that and there was a large flame just sitting on the surface of the water for a couple seconds...really cool