I believe that Masturbation is wrong, however it can be justified in certain extreme circumstances. I will examine several scenarios and determine their wrongness
Scenario 1: I jerk off to my crushes Instagram pics
Is this a sin: Yes
This is a sin because I am committing lust, a sexual act, on someone who did not consent. I am thus stealing her humanity and reducing her to a sexual object.
Scenario 2: I jerk off to a porn actress
Is this a sin: It might be
I am committing lust unto the actress, however she did imply consent by uploading the video to a porn website specifically meant for masturbation.
Scenario 3: I jerk off to my own imagination
Is this a sin: No
Since I am using my own imagination, I am become a creator and a dreamer, just like God himself. By putting myself in God's position I can better understand the Bible. Not only is this a non-sin, it may be spiritually healthy.
Scenario 4: I fuck a sex robot
Is this a sin: Yes
The Robot, is not a human being, and since I am having sex with it, I am implying that human love can be obtained by objects, or that objects and humans have the same value. This is insulting to God's creation and thus a sin.
Scenario 5: I jerk off to gay porn
Is this a sin: maybe
On one hand, homosexuality is a sin and the actors in the video are sinning. But, they did imply consent to me jerking off by uploading it to a porn website. But is it a sin to masturbate to sin? Perhaps God appreciates me only jerking off instead of asking out a boy in real life. Or maybe I'm deluding myself.
Scenario 6: I jerk off to myself in the mirror
Is this a sin: No
I am a good looking guy and I occasionally jerk off to myself. I'm sure other boys in my grade have jerked off to me as well. I consent to myself masturbating to myself and I am a human worthy of love, there is thus nothing wrong with this.