See the epic of Enki and Ninhursga: “Uttu enticed her all too willing great-grandfather, the Sumerian subterranean freshwater god Enki” (S. Shifra and Jacob eds., In Those Days: Anthology of Mesopotamian Literature in Hebrew [Tel Aviv: Am Oved, 1996], pp. 64–66; in Hebrew). In Greek literature, Myrhha (or Smyrna) fell in love with her father, King Cinyras the Cyprian, “and climb[ed] into his bed one dark night, when her nurse had made him too drunk to realize what he was doing” (Robert Graves, The Greek Myths [London: Penguin, 1960], sec. 18h, p. 69).
The word recalls a method of taking an important vow in which one person would put his hand “under the thigh” of another (see Genesis 24:2–3, involving Abraham and his servant, and Genesis 47:29, concerning Jacob and Joseph). Nahum Sarna explains that “interpreters are unanimous that the thigh refers to the genital organ” (Genesis, JPS Torah Commentary [Philadelphia: Jewish Publication Society, 1989], p. 162). Also see R. David Freedman, “‘Put Your Hand Under My Thigh’—The Patriarchal Oath,” BAR 02:02.
Uncovering the wing of the coat or cloak means having incestuous relations (see Deuteronomy 23:1 and 27:20 in the NJPS version), while taking shelter under the wing of a man’s (or God’s) coat or cloak refers to marriage or symbolic marriage (see Ezekiel 16:8).