The control stick, also known as the analogue stick is the grey stick on the Nintendo GameCube and Nintendo 64 controllers, the white stick on the Nunchuk, or the two white sticks on the Classic Controller.
In the Super Smash Bros. series, the control stick has four primary directions that can be input. During gameplay, tilting the control stick sideways will make a character walk in that direction. Tilting the control stick downward will make a character crouch, or fast-fall if the character is airborne. Tilting the control stick upwards will cause a character to jump, but only if the Tap Jump control function is enabled. The control stick can also be directed at perpendicular and diagonal angles, which will allow for more precise movement in the air, and will allow some attacks to be angled. Outside of gameplay, the control stick can be used to navigate the menu.
The control stick can also be 'smashed' to achieve various effects such as dashing, smash attacks and making certain special moves more powerful. When handling the Wii remote sideways, the directional pad serves as the control stick, as there are no control sticks on the Wii remote alone.