Question: How does the creature, which is 100% desire, restrict itself? What is the spiritual action called Tzimtzum (Restriction)?
Answer: The creature was created by the Light. The Light that operates within the creature makes it possible for the creature to overcome and control its desire and even perform actions against its desire. Under the influence of the Light, the characteristic to oppose itself is discovered within the desire.
Malchut, which receives the upper Light, feels its influence, its love, and feels shame from the lack of compatibility with the Light, the Creator. As a result of feeling shame, it invites a reaction in its desire that compels it to stop receiving the Light. The desire remains, only the act of reception is restricted.
Question: Is it possible to make a restriction on the desire to receive without feeling shame?
Answer: No, without feeling shame, there will be no drive for the creature to perform an action that is contrary to its nature.
From the Kabbalah Lesson in Russian 3/19/17