Mbh 12.165.1d

That Brahmana who summons to his bed an unmarried maiden, or suffers a Sudra, thinking him worthy of respect, to sit upon the same carpet with him, should sit on a bed of dry grass behind some Kshatriya or Vaisya and give him respect in that fashion.[475] It is in this manner that he can be cleansed. Listen, O king, to my words on this subject. The sin that a Brahmana commits in a single night by respectfully serving a member of a lower order or by sporting with him in the same spot or on the same bed, is cleansed by observing the practice of sitting behind a Kshatriya or a Vaisya on a bed of dry grass for three continuous years. A falsehood spoken in jest is not sinful; nor one that is spoken to a woman, O king, nor one that is spoken on an occasion of marriage; nor one spoken for benefiting one's preceptor; nor one spoken for saving one's own life. These five kinds of falsehood in speech, it has been said, are not sinful. One may acquire useful knowledge from even a person of low pursuits, with devotion and reverence. One may take up gold, without any scruple, from even an unclean place. A woman that is the ornament of her sex may be taken (for wife) from even a vile race. Amrita, if extracted from poison, may be quaffed; women, jewels and other valuables, and water, can never, according to the scriptures, be impure or unclean. For the benefit of Brahmanas and kine, and on occasions of transfusion of castes, even a Vaisya may take up weapons for his own safety. Drinking alcoholic liquors, killing a Brahmana, and the violation of the preceptor's bed, are sins that, if committed consciously, have no expiation. The only expiation laid down for them is death. The same may be said of stealing gold and the theft of a Brahmana's property.