Plunging into the Target
Mindfulness has to stick to the object of meditation. It has to reach it, and stick into it. There is a Pali phrase that describes this: okatittova pavattati. It means “plunging into the target.”
Mindfulness should be pakkandana, meaning “hastily speeding” or “hurriedly rushing” toward the object. As soon as an object arises, one has to note it hastily. It is necessary to use very good aiming and very good effort, since an object arises right now and it also vanishes right now. No sooner has it arisen than it disappears. So you have to catch up and follow it as closely as possible. Nothing else matters. There is no time for anything else, especially not for thinking. There is no time to ask why, what and how. Otherwise the mind will not reach the object but miss it.
Early on, mindfulness has no speed. But when it plunges into the object, some speed is gathered. For regular meditators, the speed of mindfulness gradually increases over the course of time. If you have gaps of unmindfulness, if you have the habit of taking little breaks and rests, you have to learn how to increase the continuity.