In the game, you have many frames out of a jump to be able to do a Bounce or a Kick.

When you press A to bounce in the air, the game delays the actual slamming down of Pac-Man. In the time of this delay, you can quickly slide your thumb to the B button to interrupt the Bounce with a Kick. This stores the bounce for the next time you jump, causing the "Double Tap".

You can't activate Bounce storage late into your jump, as you cannot kick flip when you're descending.