It sounded like a bad description of drag soldering which involves dragging a ball of solder over the pins with the iron and relying on the solder mask and surface tension to make a good connection on each pin.
Yes, judging from YT videos of drag soldering, this was what he did, except unlike people in those videos, he did it holding the circuit board vertically and hence it was one very quick move. Bear with me: this was almost ten years ago, I had nothing to do with electronics since, and I am not a native speaker of English!