"An A press actually has three parts to it. When A is pressed, when A is held, and when A is released. And together, this forms one complete A press. Now, usually, it's the pressing that's useful. Because that's the only part that makes Mario jump. However, sometimes it's sufficient to just use the holding part, which allows Mario to do little kicks, to swim in water, to fall slowly while twirling, and to fall slowly with the wing cap. And as for the release, well, there's currently no cases where that's useful or important, so don't worry about that part. Except for 8-2, where you could save 2 minutes, by not jumping directly into the mole and just PB by 4 minutes."