Cool; yea. About 30 years ago Skin Diver Magazine explained how to blow bubble rings while at deco stops. I can do it, but it simply rises and doesn’t have the cohesion of the dolphin bubbles. Perhaps since the dolphin blowhole is more similar to our nostrils than our mouths there is a mucus factor. Hmm, I just got an idea mate a "luggie" with a deco ring and see what happens? Next time I’m down I’ll try it and let you know how it turns out.