Likutei Moharan 36:4/ליקוטי מוהר"ן ל״ו:ד׳

14. Now, all this is so when a person has a [lustful] thought occasionally. Then, it is enough to recite the above mentioned two verses. But if, God forbid, he regularly has thoughts about the all-encompassing desire, and cannot disengage from it, then he also has to shed tears when accepting the yoke of the Kingdom of Heaven.

2For it is brought <in the Shviley Emunah> that the tears come from the excess matter of melancholy. Melancholy is the spleen, which is an aspect of the Kingdom of Evil, the promiscuous woman, from which come the souls of the mixed multitude. And when he sheds tears <while accepting the yoke of the Kingdom of Heaven>, then the excess matter—i.e., the lustful desires which stem from the turbidity of the blood of the spleen and from the excess matter—are expelled and come out. He thus includes his soul in the Kingdom of Heaven.

3This is as Yonatan renders the verse “they were weeping at the entrance to the Tent of Meeting” (Numbers 25:6): they were weeping and reciting the Shema. They did this only so that they might be spared from <lustful> thoughts, which is the shell that precedes the fruit, and so come to a revelation of Torah.