Valve stems are used to keep the air in a tire. They have a pin in their center that is depressed in order to allow air into the chamber, then immediately pops up to keep the air in. Once in a while this stem will become loose and cause a leak in the tire; when this happens, the valve stem must be tightened.
Turn the valve stem clockwise as far as you can with your fingers.
Hold the valve stem while you turn the valve tool clockwise onto the top of the valve stem. This action will attach the valve tool to the valve stem.
Continue turning the valve tool clockwise until the stem is tight.
Hold the valve stem and turn the valve tool counterclockwise to remove the tool from the stem.
