I'm also inclined to agree that it's a reflux/regurgitation-type event. There wasn't mention of nausea, sweats, headache, apathy, or the muscular contractions of vomiting; things usually associated with motion sickness. Also different from typical motion sickness is the "dry mouth" and this may be the result of the exertion mentioned in playing with the toy. Exertion and stimulation of the sympathetic nervous system may have also resulted in changes to diaphramatic muscle tone which lowered support for the esophageal sphincter -- i.e. under stress, some people barf.
If such events continue, I suggest taking note of the circumstances, including the time of day and relationship to eating. And as disgusting as it sounds, it may help to also note the explusion force, contents, color, and odor of the vomitus.