My 5 year old has a condition called gastational reflux disease and behaves the same way. He gags alot and throws up often. When he was younger many doctors told me that he was doing it for attention but I just didn't belive that a child that age could actually enjoy that type of behavior so I took him to a specialist who tested him to find out that his stomach never stops producing acid and he was inducing vomit as a way to rid his stomach of the acid that was upsetting him. Once we got him on proper meds he stopped altogether. My advise...please talk to your doctor. If this is a medicial condition and it is not looked at it could cause your child permant damage. Please talk to your doctor.