Blehj is a universal word that can be used as any part of the sentence. It is often used in friendly and fun situations as it replaces a name of a person who you are somehow familiar with. Can be also spelled Blej.
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.