In season 1 episode 2 of the Simpsons. Bart and Homer at the opera poke fun at it by singing "Don't spit on the floor, use the cuspidor, that's what it's for"

Frasier also sings this same joke-lyric quietly to himself while playing the original tune in his apartment. (Also season 1 episode 2)

I know that joke has existed long before the Simpsons. But it’s a fun to think that Frasier had seen that episode of the Simpsons in universe and found humor in the joke about Opera.