Tamar fucked with her Father-in-Law Judah (Bible Genesis 38)

Chapter 38 At that time Judah left his brothers and went

down to stay with a man of Adulam named Hira.

There Judah met the daughter of a Canaanite man named Shua.

He married her, and lay with her.

She became pregnant and gave birth to a son, who was named Er.