Top definition
When you use pictures of women in bikinis on Facebook in order to masurbate. Often times done at work where the porn sites are blocked.
Guy 1:Hey, I'm gonna go Mastur-book in the bathroom.

Guy 2: To who?

Guy 1: Lisa. She just added some super hot Panama City pics.
by yamitl April 24, 2011
Happy St. Patties Day!
When you close your eyes and randomly hit a letter into your facebook search bar and jerk off to the first decent girl on the results.
*Thinking to self*
I don't know who to jerk off to... I'll just masturbook
by BlahBlahxx54 August 04, 2011
Happy St. Patties Day!