As nouns the difference between buns and bung
is that
buns is while
bung is a stopper, alternative to a cork, often made of rubber used to prevent fluid passing through the neck of a bottle, vat, a hole in a vessel etc.
As a verb bung is
to plug, as with a bung.
As an adjective bung is
(australia|nz|slang) broken, not in working order.