Odd trick of the pack, trump and no friend of carrots

the donkey belonging to the four masters ("no friend of carrots") though of course a donkey IS a friend of carrots. (though from the carrot's perspective, the donkey eats you so maybe he's not your friend even though he likes you)

the earlier part of the phrase is trying to place the donkey within the pack of cards, he's the "joker" perhaps (odd trick), or a trump card.