Core the pineapple and cut into 3cm chunks. Place 8 small handfuls of pineapple, the lime juice, half the mint and the sugar into a pitcher and mash up with the end of a rolling pin or a fat wooden spoon.
Pour in the cachaça and a little crushed ice, then pour into 8 glasses, and add more crushed ice. Pour the pineapple juice over, filling to the rim. Garnish the glasses with extra mint sprigs and cocktail sticks with pieces of pineapple threaded on.