I'ma get after the saga of Judah and his fam (Gen. 38:1-30). First, Judah meets and marries Shua, who pops out, in succession, Er, Onan and Shelah, all boys. Then Judah does the dad thing and hooks Er up with a wife, Tamar. But Er ticks off the G-O-D, and is smote, which is where our story gets interesting:
Then Judah said to Onan, "Join with your brother's wife and do your duty by her as a brother-in-law, and provide offspring for your brother." But Onan, knowing the seed would not count as his, let it go to waste whenever he joined his brother's wife, so as not to provide offspring for his brother. What he did was displeasing to the Lord, and He took his life also. (Gen. 38:8-10)AHA! We have found the famed source of the biblical ban on masturbation. Except there seems to be one key thing missing from the passage ... you know, like any mention of self-love. The argument against goes, "Onan was killed by God for 'spilling his seed,' hence don't masturbate or you will be displeasing in the eyes of the Lord."
This is where one of my favorite things in the world comes into play. I like to call it "context." See if you read those three verses oh, say ... TOGETHER, Onan is struck down because he "spilled his seed" -- in a blatant refusal to participate in the waaaaaay outdated practice of levirate marriage, which by Deuteronomy is already made optional through Halizah, and is frowned upon by Talmudic Times. (Good look, Jewish Encyclopedia.)
Not to mention that Leviticus 16-18 says that an emission of semen just means you gotta take a bath, wash anything you busted on and then wait til evening to be ritually "clean." (We can all just pretend I knew that offhand, and didn't get an assist from say ... Wikipedia.)
If anything, you could say this is an argument against pulling out, and then streeeeetch it to contraception being bad news bears. But again, those would both be in the context of being selfish, not giving your brother's wife a heir and just sleeping with her for kicks. Which we should all be able to agree is pretty weird. Unless you're from West Virginia.
Hence, for the moral of the story, I'll quote a Jew we all know and might be more than a little skeeved out by:
"Don't knock masturbation -- it's sex with someone you love"