Onanism spilled his semen (sperm) on the ground when he went in to his brother’s wife, so that he would not give offspring to his brother. (Genesis 38:9). 

Thus the word Onanism was coined, meaning ejaculating outside the vagina, or masturbation (because this also spills semen, rather than using it for procreation or ejaculating it into the woman).

The act of Onanism (Onan) is commonly practiced in pornography films, projecting the image of using women as sexual objects that helps the men to reach the climax of orgasm, when he is about to release his seed (semen or sperm), he then takes out his penis and ejaculates his semen (sperm) on the ground.

The ritual of Onanism was also practiced in the ancient times by pagan worshipers, in the acts of orgy and group sex. Through the Ejaculating of their semen out of the women, this was a form of act that enabled them to give their semen to the spiritual beings (succumbs and incubus), the demons of masturbation.

This act was also taught in the pagan ritual called sex magic.