dog and pig and down

It's an elegant venetian expression which means "Can dal porc e zò!", and it is used to exclaim astonishment.

You: "dog and pig and down!"

Pig It Down

Pig it down
Say you've just finished the gym in Salisbury and you're eating a subway. Someone walks past you and says PIG IT DOWN

Person: eats finishes gym and sits on a bench to eat a Subway
Person 2: *walks past* PIG IT DOWN
Person: what a cunt