For an article that covers a number of these euphemisms, see S.H. Smith, “‘Heel’ and ‘Thigh’: The Concept of Sexuality in the Jacob-Esau Narratives,” Vetus Testamentum 40 (October 1990), pp. 464–473. Modern Hebrew likes euphemisms, too: www.haaretz.com/jewish-world/jewish-world-features/.premium-1.667193.