1) Pants worn while enjoying pizza. Old trousers, or in a stain-hiding color or pattern.
2) Pants one is relegated to wearing because you have pizza butt ,aka fat pants.
3) Pants in which one has experienced a pizza-related GI event, aka squirts
4) Theoretical pants made from pizza. Not a real thing, don't be stupid.
2) "Can't wait until spring when I can get some exercise, lose some weight, and ditch the pizza pants."
3) "I had to take the bus home early, and change outta my nasty pizza pants. I am never going to Pizza Hut again."
4) "Seagulls attacked me in the parking lot. Teaches me for wearing pizza pants."