A slang term referring to the idea of an old, non cleansed area underneath a males penis. Usually, From-Unda-Cheese is used as a deragotory term to insult or make fun of a boy who doesn't wash his genitals, or even shower at all. The word can also be used to play a joke on a female or male because when said quick enough, it sounds like Fromundacheese... which could quickly be interpreted as a type of cheese.
1) "Eww... hes got some serious From-Unda-Cheese, I can fucking smell it."
2) "Hey Katie!"
"(laughing under breath).. Do you like Fromundacheese?"
"It's a kind of cheese, it's really tasty on macaroni."
"(decides to act like she has eaten it before),,...Yeah! Its my favorite kind of cheese lol."
"(starting to crack up)... lol cool..."
"What's so funny??"