Tap

SPIGOT

You might turn this to release liquid from a barrel or keg.

"Tap" can mean a faucet or the act of drawing liquid from one, which directly points to "spigot"—a valve used to control the flow of liquid from a container. The wordplay is straightforward here, as "tap" serves as a synonym for the answer. In everyday language, you might "tap a keg" using a spigot, making the connection clear.