Psilocybin

Psilocybe mexicana, Stropharia cubensis (magic mushrooms)
Psilocybin is a tryptamine hallucinogen whose sensory stimulation apparently includes aphrodisiac properties. The grassland mushrooms which are the source of the drug were used by primitive cultures for tribal orgies. Today psilocybin is a Schedule One drug, illegal in the United States.
An odd side note is that magic mushrooms are useful in curing liver diseases.