Mush mouth is a particularly
involving crackers (typically saltines but anything dry will work). It is performed by chewing up enough
crackers to render one incapable of speaking clearly, receiving a load in the mouth, mixing it all together, then slowly
pushing it out of the mouth to run all over the face and make
a gunky mess.
man: oh baby here it comes.
woman: mmmfff mff mmm mm.
wide. ohhh yeah...that's a pretty mush mouth!