put on the (old) feedbag
slang To begin eating; to have a meal. I can't wait to get to Grandma's and put on the old feedbag. She always cooks the tastiest food! What do you say we put on the feedbag before we head out?
put on the feed bag
Also, tie on the feed bag. Eat a meal, as in Come on, it's time to put on the feed bag. This slangy term, alluding to a horse's feed bag that is literally tied on, dates from the early 1900s.