Masturbation and Onanism are two totally different sins

I want to address this topic because the more I teach “What does the Bible say about sex” to teens, the more I realize the confusion between these two sins. I even remember hearing while I was growing up that masturbation is wrong because you spill your “seed” on the ground like that guy in the Bible and God condemned him.

I would like to use this article to clarify the difference between the sin of masturbation and the sin of onanism. Unfortunately, the dictionary calls onanism masturbation but as we will see from the Biblical example, onanism is not masturbation. Onanism is not just simply a man spilling his seed on the ground.

What does the Bible teach about masturbation?