USA, 1955—a dummy used in vehicle safety tests to assess the effect of crashes, collisions, etc., on the driver and passengers of the vehicle—also, figuratively: a person or thing used as a test subject
UK, 1882—‘penny’ refers to inexpensiveness, and ‘puzzle’ to the mysterious nature of the ingredients—perhaps also in humorous allusion to ‘penny puzzle’ in the sense of a puzzle-card sold on the street for one penny
also ‘in a wad’, ‘in a knot’, etc.—to become unduly agitated or angry—the plural noun ‘panties’ refers to short underpants worn by women or girls—American English, 1975
UK, 1839—jocular variant of ‘penny-a-liner’ (i.e., a journalist who was paid at the rate of a penny a line, a person who produced mediocre journalistic work) with the implication that such journalists fabricated falsehoods
mid-19th century—a small bonnet standing far back on the head, which was then fashionable—also occasionally in the extended form ‘kiss-me-quick, mother’s coming’
to live in excessively close proximity or interdependence—1762: “the company squeezed themselves into one another’s pockets” in a letter by Horace Walpole
UK, 1904—refers to the action of making someone stop chattering—from the colloquial imperative phrase ‘cut the cackle (and come to the horses)’, meaning: stop talking (and get to the heart of the matter)