There are two passages in Leviticus which discuss the degree of uncleanliness one should associate with sleeping with a woman during her period.
And a woman who will be discharging, blood will be discharging in her flesh, seven days will she be in her menstrual defilement, and all that touches her will be defiled until the evening. And all that she will lay upon during her menstrual defilement will be defiled, and all that she will sit upon will be defiled. And all that touches her couch will wash he clothes and bathe in water, and he is defiled until the evening. And all that touches any pot which she will sit upon, will wash his clothes and wash in water, and is defiled until the evening. And if it is on the couch, or on the pot which she sits on, as it touched it, it will be defiled until the evening.
And if lay a man will lay with her, and her menstruation will be upon him, and he is defiled seven days, and all the couch which he shall lie upon will be defiled.(S)
But later, in the sex-law chapter, we find another ruling about the same act: Leviticus 18:19
And to a woman in her menstrual defilement, you will not approach to reveal her nakedness.
Concluded with 18:29
Because any that does of any of these abominations, and the souls that do so will be cut off from among the people. And you kept my commandments, to not do from the abomination statutes which were done before you, and you will not be defiled in them. I am Yahweh, your God
Why two punishments, of completely different severity, for the exact same act? What is the punishment for sleeping with a menstrual woman?