6. The exclusive position of the marital union is with the wife lying on her back, facing up, and the husband lying upon her, facing down. This way of union is the select and most perfect union, which the Torah desires. This is called, "the face to face union." Any other position is almost certain to bring about the spilling of semen in vain. If the woman is on top of the man, this is considered brazenness (Shulchan Aruch, 240:5) and the pull of gravity will surely cause the wasting of semen. The same is true if they are standing or sitting. Anal intercourse is considered an act of loathsome brazenness. Besides the absolute spilling of semen in vain, this is considered in the Kabbalah like sacrificing one’s children to the idol Molech. Intercourse from the back is also brazenness, even if the organ of the Brit is inserted into the proper place, and the pull of gravity will cause the spilling of semen in vain from the wife, since she lies on her stomach. Furthermore, because the strongest of klipot surround the buttocks of the woman, when the Brit passes by this impure area, it will be polluted by klipot and these klipot will be transferred to the wife’s sexual organ and to the offspring of such a union. Only in the case of physical handicap or advanced pregnancy may this positioned be approved by a qualified rabbinic authority.
7. Oral sex is certainly not kosher, causing the eyes to see what is forbidden to see, and causing the spilling of semen in vain.
Rabbi Levy adds: "Please know my brother and friend that all of these unholy unions that are mentioned above, if they are engaged in, they are not kosher in their very essence [even though they are permitted by halakha – Shmarya] since they bring about the wasting of semen, and this in turn creates a multiplicity of evil spiritual forces which bring sickness, tribulations, and damage to one’s livelihood, for all of the pain and sorrrow that befall the Jewish People in this world stem from unholy unions like these, may the L-rd save and guard us from them. Make an accounting of your soul, how much you will have to pay, and what needless sufferings come from these matters, that were done without thought, without a reverence for G-d, and without a feeling of shame, all of which cause sorrow to our Father in Heaven, and bring about a lessening of light and beneficence from the Shechina." …
9. As a warning, the wife should continue to lie on her back after marital relation for approximately ten minutes, and not turn on her stomach or side, and not immediately rise from the bed to go the bathroom, so that her husband’s semen should not flow out from her and cause the wasting of semen.
10. Similarly, the husband should not withdraw from his wife immediately after relations, but rather remain lying upon her another several minutes, and not withdraw while his organ is rigid, for this causes drops of semen to spill out.
Jews, these are your rabbis. Run away, as fast as you can.