When a girl gives you a blow job while you are playing Xbox. A joystick is a stick on your controller and a nickname for your dick, so a joystick is getting your dick sucked while playing Xbox.
I wanted to play Call of Duty last night so my girlfriend gave me a joystick.
1. the penis when gets erect and moves up and down, and side-to-side, or in a circle, either independently or when someone else grabs it and moves it in said direction themselves, like a video game controller
2. an overactive penis
His girlfriend was so horny, she moved his joystick in all directions in the middle of the night while he slept.