<v> British Slang;

1) To shit.

--> The term derives from the phrase "I must have a crap" in that 'Must have a' rhymes with 'Mustafa,' and hence, sounds like a name of Arabic origin. Chat with the Arabs came from this similarity.

--> Although this phrase may offend some people, offence is without just cause, as the phrase plays on a name in the same way that 'Hugh Jass' plays on a Scottish name.