What is foaming?

I have seen posts where people say they are foaming or have the foamies. What does that mean?

When you ate too much, dry meat , etc and it causes your mouth to water and gets slimy and usually you end of throwing up

Usually accompanied by nausea for me. Overproduction of saliva and general feeling of wanting to throw up. I've had the foamies a few times but haven't thrown up.

doesn't even have to be eating too much. Sometimes things just don't agree and it can cause foamies.

I've had it twice after taking one bite too many. Literally foaming saliva at the back of my throat. Just awful.

I thought it was heartburn when it happened to me