Continuing in a similar vein with another Paul Simon song, Kodachrome.
It's about masturbation, or at least this part is:
If you took all the girls I knew when I was single
And brought 'em together for one night,
I know they'd never match my sweet imagination.
And everything looks worse in black and white.
Those who would sacrifice an essential liberty for a temporary security will lose both, and deserve neither. -- Benjamin Franklin