In Greek mythology, Priapus was a minor god of rustic fertility, protector of livestock, fruit plants, gardens, and male genitalia. Priapus is marked by his permanent and exaggerated erection, which gave birth to the medical term priapism. He has become a popular figure in Roman erotic art and Latin literature and is the subject of a collection of often obscene and humorous verse called the priapeia. The image is from the Casa dos Vetti, Pompeii.www.ancient-origins.net/fertility