1. (v). When someone takes a noggin nose dive. 2. See Eat Shit. To mistakenly fall on one's face in an embarrassing or Derpish fashion.
My roommate threw me a goldfish snack and I missed it and totally turf derped on my bed.
He missed the soccer ball and totally turf derped.
I kicked the barstool out from under him and he turf derped so hard I snorked.