looking sketchy by wearing your hood up and dressing in dark colored clothing. To completely be murking you must also be making a gurgling/ sucking noise (tongue also included).

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).