Place an ace of diamonds behind an ace of spades to begin the magic trick. Turn the cards so you can hold them where the longer edges are at the top and bottom.
Pinch the cards together between your thumb and your index, middle, and ring fingers. Keep your fingers together. Your ring finger should be near the bottom of the card, and your thumb should be centered over your index and middle fingers.
Bring your free hand in front of the cards and quickly flick the cards back toward you. At the same time, quickly slide your middle and ring fingers downward until they hit the heel of your hand that's holding the cards. The ace of spades will be pulled backward and rest directly behind the now-visible ace of diamonds, which will be held between your index finger and thumb.
Slip both cards into your jacket pocket to complete the card color change trick, as soon as the spectator has registered the change.