Putting a vacuum cleaner nozzle up one's anus and leaving on suck until it looks like you are breathing in very deeply.
Also known as a vacuum enema.
Murking may only be confirmed if there is the presence of faecal matter inside the vacuum cleaner after the attempt.
N.B. most 'murkers' have a general use vacuum cleaner and a separate vacuum cleaner specially for murking (this is done for reasons of hygiene).
Fancy coming 'round mine for a 'murk'?
You have been 'murked'!
Is the pope a 'murker'?
Nancy had a 'murking' party.