Mbh 1.122.4

“Thus, O timid one, was the existing usage established of old by Swetaketu, the son of Uddalaka, in defiance of antiquity. O thou of taper thighs, it hath also been heard by us that Madayanti, the wife of Saudasa, commanded by her husband to raise offspring went unto Rishi Vasishtha. And on going in unto him, the handsome Madayanti obtained a son named Asmaka. She did this, moved by the desire of doing good to her husband. O thou of lotus-eyes, thou knowest, O timid girl, how we ourselves, for the perpetuation of the Kuru race, were begotten by Krishna-Dwaipayana. O faultless one, beholding all these precedents it behoveth thee to do my bidding, which is not inconsistent with virtue, O princess, who is devoted to her husband, it hath also been said by those acquainted with the rules of morality that a wife, when her monthly season cometh, must ever seek her husband, though at other times she deserveth liberty. The wise have declared this to be the ancient practice. But, be the act sinful or sinless, those acquainted with the Vedas have declared that it is the duty of wives to do what their husbands bid them do. Especially, O thou of faultless features, I, who am deprived of the power of procreation, having yet become desirous of beholding offspring, deserve the more to be obeyed by thee. O amiable one, joining my palms furnished with rosy fingers, and making of them a cup as of lotus leaves, I place them on my head to propitiate thee. O thou of lair looks, it behoveth thee to raise offspring, at my command, through some Brahmana possessed of high ascetic merit. For then, owing to thee, O thou of fair hips, I may go the way that is reserved for those that are blessed with children.’