Fill one’s boots

This expression means to help oneself to as much as one likes and these days appears to be an expression favoured by sports commentators. Footballers and cricketers invariably fill their boots i.e. score as many goals or runs when these are on offer. The origin is thought to be naval from the late 18th century when sailors’ leather tankards were known as boots. From this association, fill your boots used to mean drink as much as you want.