FYI - Some people believe that the well documented act of Onan somehow instituted a physical doctrine of YHWH warning its participants that masturbation in ANY form could possibly get you killed.  But in my mind, once you take this OVERT act of YHWH to provide an OBJECT Lesson to their creation that DISREGARDING the applicable marital instructions as enumerated by Moshe was a BAD idea and that those instructions were NECESSARY for the furtherance of any Royal PLAN to overcome the genetic tampering of the Fallen Watchers (See Book of Enoch.); you'll get a better handle on your reality.  NO pun intended.

There are certainly OTHER considerations in determining whether or not your personal decision to seek carnal self-release may somehow TEMPORARILY cut you off from communication with the GOOD, Omnipotent, Omnipresent, Sentient Creator Deity as described and promoted as existing in the UNMODIFIED Ancient Hebrew Scriptures and later Good News! of the Apostles expounding upon the Old Covenant FULFILLMENT through the person of Iesous The Messiah of Nazareth.  But one has only to review my "What Is Unforgivable? post to help you decide the relative eternal TRUTH of this matter.

NOW, some insights into this subject CAN be gleaned from very OLD but relevant recorded thoughts about the VAST difference between what YOU think and what the True Deity thinks:  Mind of A Good, Omnipresent, Omnipotent, Sentient Creator Deity 

There is also sufficient evidence of the separation that certain acts of carnality naturally create:  Carnal Mind Is Enmity  

But since INTENT is most likely a more important spiritual consideration within the context of whatever carnal act you CHOOSE to do, it may be necessary to understand the relative EASE at which one my avoid trespass by following Paul's advice, IF you are able AND Freely CHOOSE to do so, or entering into and maintaining a healthy, temporal legally authorized and Royal Instruction sanctified marital relationship.

UNFORTUNATELY for our reality The Beast certainly encouraged the FORCED celibacy of certain lay ministers or nuns seeking to serve the greater good as a member of the ecclesiastical body which would also trick it's adherents into believing that a TEMPORAL "father figure" priest was actually authorized to hear a carnal confession and somehow propitiate the forgiveness of whatever act had been accomplished or was contemplated along with any suggested PENANCE.

You MAY surmise that a person FORCED into unnatural celibacy and upon hearing any salient descriptions of these contemplated or completed carnal acts might be severely TEMPTED to think and act upon them personally whenever they find themselves alone in their cloistered rooms. 

Whether or not this FORCED and unnatural celibacy is what has led to COUNTLESS reports of pedophilia (And most likely COUNTLESS more unreported cases), of these unnecessary "father figure" priests is anyone's guess but it doesn't take a rocket scientist to figure out that the CARNAL mind will always try to find a way to satisfy it's needs, REAL or imagined.

Oh, and to jump back to the original thought concerning Onan's Temporal Punishment, I'll leave you with this explanation of the Son of Man to a certain sect of Jewish Priests who for whatever reason, were denying the doctrine of resurrection from the dead.  One Bride For Seven Brothers  Believe it or not.  Till then.  Shalom!