Use the verb douse to describe covering something with water or other liquid. When you're camping, you douse the campfire with water when you're done with it.
Douse often involves water, but you could also douse your French fries in ketchup. Douse can describe the act of extinguishing a candle, or even turning off a light. You might douse your bedroom light when it's time to sleep or simply douse a candle by blowing it out. Douse is most commonly pronounced to rhyme with mouse.