It sounds as if he is having a ball getting a response from you!! My cherub went through the same, experimenting with how far she could spit, spray, throw her food! the more I reacted the funnier she thought it was! I started saying"Oh well you're not hungry then, I'll put it away"' There was no reaction, except that I would take the food away. She would yodel. I would tell her if you are hungry, eat it, no playing! Then I would put it back. When she did the right thing, I would praise her, sit with her and help her eat it. Once the spitting throwing started again, I would put the food away and take her out of her chair. I wouldn't growl or react as this feeds the behaviour. It is hard not to laugh sometimes as it is quite funny! They are usually only trying to engage you and they know they can get a reaction over the food thing! Good luck!