A yeast monger is a woman with a sexually transmitted disease.
She is called a "yeast monger" because such fungal diseases
as Candidiasis are known medically as "yeast infections" and are (or can be) sexually transmitted
Oh man bad mistake to make. Didnt you know that she is a yeast monger? everyone says she is.
Darnit I thought something tasted funny when I was licking them beef curtains