ins-and-outs
noun► want to know the ins-and-outs of a cat's arse; want to know the ins-and-outs of a duck's arseto be very inquisitive. Generally in catchphrase form as 'you want to know', 'he'd want to know', etc. Variations include 'the ins-and-outs of a nag's arse', also 'of a duck's backside' and 'of a duck's bum'
UK, 1984