After searching every nook and cranny of printer settings and help files I was in despair. How oh how does this option show up on campus, but not on my own laptop? Doing it manually with 50-page scripts seemed a good idea a decade ago, but I digress...
The crux of the problem: some obscure widget termed "Duplex Unit". Yes it's a breeze to activate, and no, I didn't figure that out until my supply of clickable tabs was exhausted. To locate aforementioned widget:
Computer > Control Panel > Printers > select, then right click on default printer > Properties > Device Settings > Installable Options > Duplex Unit (for 2-Sided Printing)(Apologies if you're not using some retarded form of MS Windows.)
Once you've changed it to "installed", the option to print on both sides of the paper will show up in the printer's settings (Printing Preferences > Finishing > Print On Both sides).
You can stop headdesking now.