Bulimic Baby

So, I have a bulimic baby on my hands. Easton literally is bulimic. Not in the real sense of the word but he likes to gag himself and he will do it to the point of throwing up. He has done it several times and yesterday was the worst! He was in his crib and Sam walked in to a very fun surprise of throw up all over the crib sheets, blankets and even the floor. Usually I hear him and go in running but then try to act normal when I walk in so he doesn't know that is why I'm coming in but this time I didn't hear him at all and we paid for it. I asked the doctor why he does this and he said he just thinks its interesting and he throws up because he has a strong gag reflex. He told me to ignore it but that is not always easy. I usually just try to give him a binki or something to play with but it's hard! He does it with spoons, his finger, lot's of things and he throws up quickly. I try not to overreact so he gets a reaction from me but I can't keep that up every time. Any advice out there? My crazy bulimic baby.