I have had this (or a similar dream) a few times in the past few years. Now, I suppose I can guess what the meaning is, but would like your input.

I open my mouth and stuff comes out that I spit in the garbage can. Last night it was like scalloped potatoes. Every time I open my mouth I would have this stuff, and just spit it out. When I have had the dream in the past it was slightly different. Like stuff I would scrape off the inside of my mouth or something. Wierd eh. Simple interpretation would be that I am lying about something, or running on at the mouth lol I dunno....