When gerunds take objects, a curious transformation usually occurs within the phrase. The object of the gerund takes the gerund's case, and a gerundive takes the gerund's place, changing its form to agree with the newly changed object. Are you confused about this presto-chango? Sometimes we do the same thing in English.

Ebrius fimus vinum bibendī becomes Ebrius fimus vinī bibendī.

“We get drunk by drinking wine” becomes “We get drunk by wine drinking.”

Both are acceptable constructions in each language. Latin prefers vinī bibendī, “by wine drinking”; English prefers “by drinking wine” (vinum bibendī).

Dē gustibus nīn est disputandum. (“[Matters] concerning tastes shouldn't be argued about”; i.e., “taste is not to be disputed.”)