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 someone's salt
Rur. to be someone's guest. The least you can do when you're eating someone's salt is to help them out around the house. That good-for-nothing Jim was flirting with Bill's wife at the same time he was eating Bill's salt.