To save her marriage, "Elise" tried giving her husband fellatio once every 2 days for two months. She claims it cemented their relationship [http://www.elle.fr/Love-Sexe/Sexualite/Dossiers/La-fellation-le-ciment-du-couple-2120880 (in French)]
Pedagogic erotic relationships are also documented for Sparta, together with athletic nudity for women. Plato's Symposium mentions women who "do not care for men, but have female attachments."
