Is there a clear verse or authentic hadith that prohibits masturbation, and is the verse "And those who guard their private parts, except from their wives" what prohibits it?

It is not permissible to practice masturbation. The proof of its prohibition is the saying of Allah the Almighty: "And those who guard their private parts Except from their wives or those their right hands possess, for indeed, they will not be blamed But whoever seeks beyond that, then those are the transgressors," and the saying of the Prophet, peace and blessings be upon him: "O young people! Whoever among you can afford to marry, let him do so, for it helps him lower his gaze and guard his modesty. And whoever is not able to marry, let him fast, for indeed, fasting will diminish his sexual urge."