I have seen this concept in many places (including GYE), and also in "Flames of Faith" by Zev Reichman page 65, which I read this past Shabbos:
What is the body's strongest impulse? I would argue that it is lust. Lust is a mask of a heavenly and soulful force, Chessed, the desire to spread out and connect with others.
In a footnote he explains this: It says in the Torah "A man who marries his sister... it is Chessed... and they will be cut off .." Chesed? That's a strange word for a terrible sin. The Baal Shem explained that the verse included the word Chesed to teach that lowly lustful desires are a misapplication of the Heavenly drive for Chessed. The verse is bemoaning the disgrace saying, "Lust? How could MISAPPLY CHESSED, the most radiant and important of character trait!
Lust is when I seek to connect with others, (especially of the opposite gender) for my own selfish pleasure.
Chessed is the elevated form of this urge; desire to connect with others in order to give and to help them, and an urge to attach oneself to God.
Lust, as the most virulent bodily desire, teaches that generous giving is the most powerful urge of the soul.
THE BODY'S LUST DRIVE IS ENORMOUSLY POWERFUL; THAT SHOULD TEACH US HOW DEEPLY THE SOUL DESIRES CHESSED.
Perhaps the following thought might help one overcome improper drives: The animal soul is ascendant when lust is actualized. If one acts according to the dictates of the selfish desires, one is little better than the beasts of the wild. On the other hand, when one displays selfless giving, the Heavenly soul shines through the body.
When experiencing lust temptation the body is reflecting a fallen urge of the soul. It is a moment to engage in Chesed - selfless giving to other humans and to do for G-d.