Did This Odd Hebrew Expression Come from an Afro-American Folktale?

Jonathan Mohrer writes:

I was reading a column in [the Hebrew daily] Yediot Aḥaronot this week about the upcoming Israeli elections, and the columnist made a reference to Prime Minister Netanyahu having ḥem’ah al ha-rosh, “butter on his head.” Do you have any clue as to what this means? And where does the expression come from?

“To have butter on one’s head” in Israeli Hebrew means to be in a morally compromising or embarrassing situation that should (but doesn’t always) prevent one from provoking others or drawing their fire. “She’s accusing them?” someone might say. “She’s got butter on her head!”