If you're tired of the disgusting displays of spitting food and smacking lips, take action. No one wants to eat with your child if his food isn't staying in his mouth and he's making gross noises. Early childhood is the perfect time to start teaching your child how to chew with his mouth closed. It'll take time, but soon you'll be able to enjoy more pleasant meal times.
Ask your child nicely to chew with his mouth closed. Perhaps he doesn't realize he's supposed to be keeping his mouth shut while he chews his food. Show him what you mean by putting a bite of food in your mouth and demonstrating how to chew it with your lips closed.
Show your child how gross it is to chew with your mouth open. Put some food in your mouth and chew it with your mouth open. Be dramatic. Make loud smacking sounds and spit a bit of the food out occasionally. The more disgusting the better. Your child will probably shriek with laughter, but she'll also get the idea of how gross it is to chew with her mouth open.
Think up a signal to use with your child so you don't spend the whole meal giving reminders about his chewing habits. Maybe you can point to your own mouth or press your lips together. If you see your child chewing with his mouth open, give him the signal.
Read a few picture books that teach your child about chewing with her mouth closed and other table manners. Seeing pictures of poor manners might motivate your little one to remember her own manners. Try "How to Dinosaurs Eat Their Food" by Jane Yolen. It's colorful illustrations and entertaining text provide a good lesson about proper etiquette at the table. "Please Pass the Manners" by Lola M. Schaefer showcases different animals teaching table manners. The simple text is perfect for toddlers and preschoolers.
Write "I chewed with my mouth closed" on a piece of white paper. Hang the paper on the refrigerator or near your dining room table. Each time your child makes it through a meal without chewing with his mouth open, let him put a sticker on the paper. Once he gets a certain number of stickers, let him choose what to have for dinner the next night.