Answer: It is impossible to keep pleasure in egoistic desires (Kelim). It isn’t even a pleasure but a mere spark that slightly brushes against us and dies.
Pleasure is nothing but the Light! And if you wish to keep it, you need to prepare your vessels (Kelim) that would be fit for it. If desire is in bestowal, you will experience an enormous and everlasting pleasure in it, which continuously and endlessly expands. Otherwise, there is no chance to hold on to the pleasure longer than a few minutes or seconds.
It also depends on the pleasure itself: The more exalted it is, the sharper and faster it ends. A simple pleasure may last for a while. You may stay in bed for a few hours and enjoy rest, or put a candy in your mouth and savor it for a few minutes. But if the pleasure is exalted and powerful, it comes in a form of a peak and very quickly disappears.
Indeed, it isn’t a pleasure, but rather an encounter with a spark of Light that is regarded as a “thin candle” (Ner Dakik). If you wish for pleasure to never die, you need to offer it a desire that matches it, which is the desire of bestowal.
The pleasure comes from the Giver, and your desire must also come from a giver. Then, they will meet, cling to each other, and adhere, never to part again!
From the 4th part of the Daily Kabbalah Lesson 12/30/10, “The Wisdom of Kabbalah and Philosophy”