Laying with animals is completely forbidden because during such an act the person is not copulating through the human aspect within himself, but rather through the animal within himself. It is the inner state that is being referred to here.
By this act, the individual is lowering himself to such an extent that he becomes an anima and even lower than that because he is serving the animal within himself by deriving pleasure from his animal level. That is, he desires to be the animal. In other words, his behavior, in this world, is not for the sake of rising toward the Creator, but rather for pleasing the animal within himself.
A person who engages in pleasing his animal state damns himself. This means fulfilling any animal desire, not just sexual. For example, when he feeds “his cattle” only for carnal pleasure, then he sinks lower than the cattle because he is serving it. He should be feeding his animal only in order for it to rise to the level of human, that is, one should constantly be engaged in work on the self.
Question: Does that mean that a man should only lay with a woman, with a desire, in order to birth the next level?
Answer: According to the Torah, that is how it is. In the Torah, copulation is viewed only as means for spiritual advancement, when each time the person is in the intention of conceiving the next spiritual degree. In our world it is personified by the birth of new baby.
Question: And that is why this must be done on “clean” days?
Answer: Yes, in our world, following these rules is a direct reflection of spiritual forces according to root and branch.
Question: For this act to occur only for the birth of the next degree, on whom is the responsibility greater, on the man (let’s say, even within me) or on the woman? Must she be clean?
Answer: On both. There are things that only the woman knows and is able to do, while the man is not. In this, the man completely trusts the woman. There is no way that he is able to verify. Everything is based on her honesty and sense of responsibility.
From KabTV’s “Secrets of the Eternal Book,” 11/23/2016