A phrase used in conjunction with sporting failure under immense pressure, as if someone soiled themselves after being put to the test and failing miserably. It has originated from the man whom wore brown trousers for over 20 years of his life in Ballymena county Antrim. Needless to say he suffered from being under pressure during pool billiard games.
Person A: The pressure really affected him on that last shot.
Person B: No doubt, he did a Billy Brown Trousers.
Person B: No doubt, he did a Billy Brown Trousers.
by Scrooty mcboogerballs August 29, 2010