The alias one goes by at parties to avoid tarnishing their real name through any of various embarassing actions one often performs at parties. In essence this helps to make sure that "What happens in the party, stays in the party."

It’s an acronym standing for Can’t Remember A Fucking Thing. It’s usually used to describe embarrassment at being unable to remember someone (CRAFT moment); going onstage as the lead in the latest theatrical performance and your mind goes completely blank (CRAFT situation); the next morning after a night when you got pissed as a fart and woke up in bed cuddling a traffic cone and a string of fairy lights wound round your prick.