Yeah, it drove me nuts when my son went through this stage; maybe it's a boy thing, my daughter never did it! Anyway, he stopped on his own after a little while, I can't remember for sure but he only did it for a week or two. I think the sound bothers us more than it actually hurts them to do it; unless it interferes with his eating or seems to hurt him, I would say just wait it out and he will probably stop on his own. Of course, if it becomes a real concern you are losing sleep over, check with your family doc or pediatrician; even if he/she tells you the same thing as moms on here, the reassurance can make all the difference in the world somtimes!