Inuus

In ancient Roman religion, Inuus was a god, or aspect of a god, who embodied copulation. The evidence for him as a distinct entity is scant. Servius says that Inuus is an epithet of Faunus (Greek Pan), named from his habit of intercourse with animals, based on the etymology of ineundum, "a going in, penetration," from inire, "to enter" in the sexual sense. Other names for the god were Fatuus and Fatulcus.

Source: https://en.wikipedia.org/wiki/Inuus