The backwards pizza place means to have someone shove cheese, tomato paste/sauce, and garlic in your rectum before buttfucking you while saying mama mia
When you fuck someone from behind while simultaneously eating pizza off of their back. Typically pizzabacking involves pizza in a box, but fresh-hot pizza can be applied directly to a recipiant's back if they need to be taught a lesson. To simulate an acid trip, try pizzabacking while watching Hanna Barbera cartoons. If you don't have a sex partner or pizza available and you still want to simulate an acid trip, try watching Hanna Barbera cartoons.
Middle Manager with Nothing to Lose: Linda do you know the difference between a Caesar Salad and a Pizzaback?
Confused Secretary: No?
MMWNTL: Good, lets do lunch. And by lunch I mean you from behind while I eat pizza off of your back.
Short-hand for the word floccinaucinihilipilification, meaning the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language).