That Jesus did masturbate is found within the Bible itself.
For one proof, just consider the Messianic prophesy contained in Isaiah 53. There we read about Jesus Messiah "...he shall see his seed...and the pleasure of the Lord shall prosper in his hand." (Isaiah 53:10----the Hebrew 'zera' translated 'seed' also conveys the sense of 'sow carnally', or simply 'ejaculate.').
Insofar as Jesus was without reported seed or posterity, or even a wife for that matter, any seed sowing that "...he shall see...", will of necessity be "...in his hand...".
Although this prophesy does contain some very rude metaphors, they do help compose and complete the portrait of the sexually frustrated Jesus Christ.
As supplementary evidence, just consider that Jesus also periodically goes off by himself as in "And in the morning, rising up a great while before day, he went out, and departed into a solitary place, and there prayed."(Mark 1:35 and Luke 4:42); and "...he withdrew himself into the wilderness, and prayed."(Luke 5:16); and "...And he took (the Apostles), and went aside privately into a desert place..." (Luke 9:10, Matthew 14:13, and Mark 6:32); and "...he went up into a mountain apart to pray: and when the evening was come, he was there alone."(Matthew 14:23 and Mark 6:46), etc, etc, etc.
Yeah.........We've been told that demented Jesus (See Mk 3:21 for evidence of Jesus behaving like, and being branded, a lunatic.) was just praying to himself (Being a member of the Trinity of Curley, Larry, Jesus, and Moe!). You bet...!
Moving on, we see that Jesus' invitation to his followers to castrate themselves "...for heaven's sake..." was taken seriously by numerous devotees. See Matthew 19:12 for full gruesome particulars!
But, Jesus says nothing about castrating himself.
Jesus next proclaims that "But they which shall be accounted worthy to obtain Heaven, and the resurrection from the dead, neither marry, nor are given in marriage:"(Luke 20:35).
O.K.....you got that? Jesus and his castrated (Greek 'eunouchizio' translates to 'amputate the testes' in Matt 19:12) male followers go to Heaven where marriage is not permitted. [Now you can see why...!]
But there's much more to this story.
The full significance of the above passages becomes clear when we read further that "...a Lamb stood on the mount Sion, and with him...the 144,000, which were redeemed from the earth...are they which were not defiled with women; for they are virgins...These were redeemed from among men, being the firstfruits unto God and to the Lamb."(Revelation 14:1-4).
These 144,000 elect males will remain "...undefiled with women..." for all eternity because "For in the resurrection they neither marry, nor are given in marriage, but are as the angels of God in heaven."(Matthew 22:30 and Mark 12:25).
So where does that leave Jesus Christ?
Well, he gets to spend the rest of eternity with these 144,000 'virgin' males in the hereafter. And remember that he's got a lot to make up for...!
What a treat for Jesus! After all, 144,000 male tumescent penises placed end-to-end would measure approximately 75,000 ft., or put another way--About 15 'miles' of unblemished and undefiled virgin ("...undefiled with women...") penis for Jesus pleasure!! (remember, no marriage and all other male Jesus devotees having castrated themselves in accordance with Jesus' instructions in Matt 19:12)!)
Certainly enough to keep even Jesus occupied for all Eternity!
Hey Jesus, finally over the top, Huh!