A little pearl like ball, in a Blackberry (cellular phone), which makes navigating easy, but can fall out if you don't take care of it, which is a pain in the ass.
Josh: Wow, your Blackberry has a Trackball?!
Mike: Whats so exciting about that?
Josh: Mine still has a scroll!
Mike: Lucky, I don't take care of my Trackball, so it often fall's out.
A slang term for a woman's clitoris.
The motion of moving your finger over a woman's clitoris as you would do with a trackball found on a Blackberry mobile device.
I spent most of the time watching the movie with my hand down my girlfriend's pants. Trackball all day, baby.