If seasoned smokers, tokers and pipe-pokers can blow Smoke Rings (and Tolkein implies such activity is the finest part of havin' a puff), surely the same technique - the same articulation of the throat and tonguing action - might be used in the forging of vomit rings.
Imagine the joyous bafflement inflicted at bus stops besplattered in acidic hoops... like the Mysterons have had a night on the tiles.
Surely there's a research grant in this. No, really.
ETA: That should be "Anagram of", not "rhymes with". I am a twat. And much in need of a holiday.