mind-masturbating

To mind-fuck oneself, often in succession; lubrication offered by drugs, alcohol, etc.

I'm mind masturbating to string theory right now.

John's Girlfriend: "Hey, want to come over?"
John: "Hold on a second, I'm finishing up mind-masturbating to Stephen Hawking talking about quantum physics and the theory of multiverses. Oh yeah, oh yeah..."
John's Girlfriend: "Oh."