(one's) little finger told (one) that

A phrase used when the speaker has learned something by unconventional means. Pain in one's fingers was once regarded as an indicator of things to come. Oh dear, I just knew that they were going to break up this weekend—my little finger told me that. A: "Wait, you already heard that Mark is planning to propose to Sarah soon?" B: "Not exactly—my little finger told me." Grandma's little finger told her that it's going to snow tomorrow, so she sent me to the store to stock up on food and supplies.