Does this mean 'the other day,' as in a few days ago, or 'the second day', as in on the second day of his holiday or whatever?
If it was "the second day" you'd normally say "på den anden dag" or "på andendagen" instead, so in this case it more naturally means "a few days ago"
It could be either.
"den anden dag" in the meaning of a few says ago could also be expressed with the Word "forleden" as in "han mødte sin tidligere lærer forleden".
I will totally use this sentence in the future
What, no comments about ducks?
Is "feeling the wind" an idiom?
They should also accept "The next day", as this would be the correct translation in English for this particular case.