Acronym, stands for Post Work Eating Binge. A PWEB is the act of stuffing ones face with food immediately on returning from work. Usually this consists of left over pizza, curry or other last nights takeaway. If last night didn't involve takeaway, the foodstuffs can be toast, slabs of cheese, ham, or other tasty morsels found in the fridge and requiring no preparation.
I was so hungry when I got home, I just couldn't help but have a massive PWEB.
Pweb is a name of a made up animal with green soggy skin and bipedal structure and an overall "froggy" look. A response to the word is often that the other person grabs his/hers cheeks, stretches them out and starts doing shortly interrupted churchling sounds.
Pwebs have been invented in UK during an English lesson as a part of a social debate concerning gypsy community.