If you go to sleep on any given day, you'll wake up the next day at 6 AM. From there, walk out behind your Ranch house and jump off the cliff to knock yourself out. This will net you this achievement! Make sure you don't have anything on you that you aren't willing to part with, as anything in your inventory will disappear when you get knocked out.
Here's my video on all achievements if you'd prefer. Skip to 1:12 for Not My Morning.