When one has the sudden realization that they are going to vomit. Or when one experiences the aweful body convulsing coughing (yurp) until the point of throwing up (yammy).
Dude that lady just won't stop coughing, hacking and yurping..I think shes gonna yammy all over the place.
Like a Yummy Mummy but without any of the redeeming features. Usually a know it all, highly opinionated and oblivious of others. Likes to start sentences with "as a mother...."
This café sucksnow, its become a haven of the yammy mammy