I've lurked at or been a member of Christian discussion communities for a few years now. It never fails that someone posts, as a new member, a thread like this. I often wonder if it is because they think they'll upset the Fundies present.
I'll say this. The creator of the universe and all that exists, seen and unseen, known and as yet unrealized, would have to be myopic with nothing better to do than monitor a man and his relationship with his penis for this to be an offense that could send that man to Hell.
While the prohibition itself is derived from the OT, the Hebrew's and their Bible. Part of the evidence that the first faith is to believe human's had nothing at all to do with wording the Bible.
It all pertains to the value of the tribes and the seed of man in the early era of the Hebrew's culture.
Tribal identity. Which is why their Bible said, paraphrasing here, it was OK to enslave a people after battle. Just as long as those persons were not of the victors tribe. (There are 12 Tribes of Israel)
This is also why there is no scripture in the OT that forbids pre-marital sex.
Because in those times, teachings, having sex would mean the couple were wed. The male would then have to pay the father of the woman he bed a 'bride price'. Disturbingly enough, this pertained to the offense of rape as well.
If a Hebrew woman was raped her rapist would have to take her as bride. Paying the father 40 pieces of silver for that "right". (That's ten pieces of silver more than what Judas received for selling out the Christ to the elders of the Temple in the NT).
However, there was a catch. If the girl seemed to enjoy her ravishing both were to be stoned to death.
God of love , tribal people of whacked!
In any case, that is the whole roundabout reason masturbation is condemned. Spilling the seed, being the Hebrew legal system was prosecuted as Patriarchal, while inheritance into Judaism is Matriarchal. I.E. Passes through the woman.
Spilling the seed in masturbation was believed to have declined and insulted the tribe's inheritance of the future.
Suffice to say, if God has nothing better to do than to watch his people self-pleasure and therein condemn them to Hell for that, those folks are worshiping the wrong god.
Orgasm is of God.
Editing for this PS.
If you masturbate more than you do anything else in your day, you need a girlfriend. Or perhaps a therapist. Seriously.