Some dictionaries list douse and dowse as variants of each other, but in real-world usage they are mostly kept separate. To douse is (1) to plunge into liquid, (2) to drench, or (3) to extinguish (especially flames). The word also works as a noun referring to a thorough drenching. The rarer dowse means to search underground for water or minerals using a divining rod, and it’s occasionally used to mean, simply, to search underground for, usually using some kind of implement.
It’s easy to find examples of douse used well in its more conventional senses—for example:
Still, if you wrap the meat in a fresh corn tortilla and douse it with the restaurant’s flavorful burnt habanero and crème salsa, it makes for a pleasing mouthful. [Los Angeles Times]
Colleagues doused the flames with a fire extinguisher and the officer escaped unhurt. [Guardian]
They reported firing 51 British-style plastic bullets … and dousing the mobs with blasts from water cannons. [Stuff.co.nz]
Because dowse is so rare in this century, recent examples are harder to find. Here’s one from an article about modern dowsers:
Don Estes doesn’t believe in ghosts, but the process of grave dowsing he practices hints at the supernatural. [Natchez Democrat]