Axl heard it and said, "we're gonna make a song about that."
Slash was like, "no, no, this is just a warm up exercise."
Of course Axl won out, and the rest is history.
The part where they start singing "where do we go now" was truly because they didn't know where to take the song at that point !
Thanks for posting.
When I was in an Army band in 1966 we had a classical guitarist, his warm up was to play Dixie as the bass line and Battle Hymn of the Republic as the treble.