I had a little boy like that and I was always asking him to close his lips and try to eat quietly. I asked his Mom if it bothered her at all and she told me it didn't because his Dad eats the same way. Okey, dokey then!!! But I couldn't eat at the table or stand to listen to it so I think that's why I got into the habit of reading stories and singing songs and kind of doing part of my circle time while they ate. I eat my lunch after they are all tucked into bed. It Is So GROSS!