Lot's oldest daughter suggests to her younger sister that they intoxicate their father and have intercourse with him.
My translation of Breishit 19:34:
"It was the morrow. The older said to the younger 'Behold, last night I lay with my father. Come, let us make our father drink wine tonight also, and come, lay with him and we will establish seed from our father.' "
Why is there a change from singular at the beginning of the verse to plural at the end, when referring to their father? It seems that the beginning of the verse, when the older is talking, should have used the plural as well.