Butter safe than sorry

Onan was a figure detailed in the Book of Genesis chapter 38, as the second son of Judah and his Canaanite wife, the daughter of Shuah. Onan had an older brother Er and a younger brother, Shelah. Onan was commanded by his father, Judah, to perform his duty as a husband's brother according to the custom of levirate marriage with Er's widow Tamar. Onan refused to perform his duty as a levirate and instead "spilled his seed on the ground whenever he went in" because "the offspring would not be his", and was thus put to death by Yahweh. This act is detailed as retribution for being "displeasing in the sight of Lord".