Consensual Sex & Masturbation
Regarding philosophy behind prohibition of Zina , please see: https://youtu.be/l16ad6WN0Q0
Yes, but there was this recent video in albayaan lectures, I cant locate it right now where he explained why state can act in adultery and in fornication even though fornication between consenting adults does not directly effect the rights of someone/ society. And about the implementation of punishment, why it is not a state law but the law of Allah that has to be carried out.