Menturbate
To mentally masturbate. The most discrete form of sexual self-pleasuring. With a good imagination and a bit of practice menturation can result in actual orgasm.
I especially like to menturbate on public transport. As long as I can keep a straight face the girl sitting next to me doesn’t even notice.
Menturbation
The act of engaging your brain in useless activity.
Ex: Sam Witwicky thinks that he can get with Mikaela Banes out of the Transformer movies, but we know he is just the victim of Menturbation.
Menturbating
To become sexually aroused mentally, but not physically, like when 40 something women watch 80's has-been pop star videos.
You can't pry Catherine away from that laptop, she's menturbating to that Rick Springfield video on YouTube.