look up any word, like doxx:
 
1.
When your mind is only focused on having sex with a hot celebrity and your girlfriend, to where absolutely nothing can break you from your sexual daydream.
Billy: Dude what's wrong with Hunter?

John: He's thinking about having a 3-way with Katy Perry and his girl Emily.

Billy: Classic case of Mindsterbation?

John: Yup.
by A pro mindsterbator August 10, 2010
 
2.
derived from the term mind-fucking, where when mind fucking one self, one tends to mindsterbate, therefore the word directs towards the situation to when a person is fucking with ones on mind he tends to be mind-fucking
Joe: I have been fucking with my mind, with all this arithmetic and alcohol

Harry: Yeah dude I guess mindsterbation of a higher form
by Maverickan September 05, 2012