Definitions for wash down
eat food accompanied by lots of liquid; also use metaphorically
"She washed down her dinner with a bottle of red wine"; "He washes down his worries with a nightly glass of whisky"
wash down, flush down(verb)
"The body washed down the river"
To help to swallow by drinking a liquid, after eating something, or taking a pill.
To wash something completely from top to bottom.