Specky does it a couple times a month. I've never seen it in my other four. I use the blow in nose trick to stop it, since it works with her. I had another dog that stopped when I lifted her head and rubbed her throat. Another would stop when I gave a sharp yell and clap, because it startled him. Some dogs just need to stop on their own. I've never had a dog do it with a long pause between like in that video. Glad you figured out what it was, because it can look scary.