to masturbate at your computer
My chica caught me mousing off last night.
or mau5 off: the act of masturbating to, near, or while listening to the electro music sensation deadmau5. Also known as mau5turbating or beating the mau5.
Joel: Yeah dude, I just finished my new dub5tep song, did you hear it?
Tommy Lee: Yeah dude, It made me mouse off. Shit was so cash
Joel: Awh man, Suck it, Noob.
Tommy Lee: Whats a noob?