you go out for a good clubbing / drinking session with alot of notes. Every time you go to the bar you pull out a note to pay with. 'Drinkers Pocket' is what you have the next morning when you put on the trousers you had on the night before. or search trough them to find your cash
last night i went out with £100. ordered a fair few drinks, the next morning i checked my pockets, i had "drinkers Pocket with around £25-£30 left all in £1, 50p and other coins.