A phrase first used by a young man called William from Central Queensland, Australia in an incident involving a dyslexic message on a get well soon card.

Originally spelt 'knok the troth'

Now in common usage as a colourful way of saying 'tap that' meaning attempt to have some semblance of sexual relations
Person 1: Look at her/him, s/he's hot!
Person 2: Would you knock the trough?
Person 1: Oh yeah!
by The Original Teeny September 9, 2006
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