The Moche of Peru are another ancient people that sculpted explicit scenes of sex into their pottery . At least 500 Moche ceramics have sexual themes. The most frequently depicted act is anal sex , with scenes of vaginal penetration being very rare. Most pairs are heterosexual, with carefully carved genitalia to show that the anus, rather than the vagina, is being penetrated. Often, an infant is depicted breastfeeding while the couple has sex. Fellatio is sometimes represented, but cunnilingus is absent. Some depict male skeletons masturbating, or being masturbated by living women.