I've encountered these things sporadically (maybe once every 1-3 months) since I was maybe six years old (twenty-one now). Every once in a while--but usually when I wake up in the morning--I'll find a small lump (think the size of those mini chocolate chips) of soft, off-white, nasty-smelling and -tasting stuff in my mouth, usually on the back of my tongue. They're irritating but that's about it.

The only thing I've heard of that are similar visually are tonsilloliths, but I don't think they are the same thing. These are never hard, are never actually stuck to the inside of my mouth, and their appearance appears to have no relation whatsoever to my being sick or having any kind of mouth discomfort. I don't have asthma, breathing problems, tonsil problems, or any other obvious health issues I could connect them to.

I'm not worried about my health, just intrigued, very vaguely annoyed, and curious if anyone else has this and knows what it is.