eat (one's) salt
To stay at someone's house. I feel bad eating Jim's salt for a week, but his house is closer to the meeting site than any hotel.
eat (one's) words
To retract, regret, or feel foolish about what one has previously said. You think I can't get an A in this class, but I'll make you eat your words when we get our report cards! After my negative prediction for the season, I certainly ate my words when the team started out undefeated.
eat pussy
vulgar slang To perform cunnilingus on a woman.
eat (something or someone) for breakfast
To defeat, complete, or handle something easily. Often used as part of a boast. He can challenge me all he wants, I'm not worried! I eat chumps like him for breakfast! If anyone can write a term paper in one night, it's Rich—he eats assignments like that for breakfast!