In ancient Roman religion, Mutunus Tutunus or Mutinus Titinus was a phallic marriage deity, in some respects equated with Priapus. His shrine was located on the Velian Hill, supposedly since the founding of Rome, until the 1st century BC.
During preliminary marriage rites, Roman brides are supposed to have straddled the phallus of Mutunus to prepare themselves for intercourse, according to Church Fathers who interpreted this act as an obscene loss of virginity. The Christian apologist Arnobius says that Roman matrons were taken for a ride (inequitare) on Tutunus's "awful phallus" with its "immense shameful parts", but other sources specify that it is brides who learned through the ritual not to be embarrassed by sex: "Tutinus, upon whose shameful lap sit brides, so that the god seems to sample their shame before the fact." The 2nd-century grammarian Festus is the only classical Latin source to take note of the god, and the characterization of the rite by Christian sources is likely to be hostile or biased.
Unlike Priapus, who is depicted in human form with an outsized erection, Mutunus seems to have been embodied purely by the phallus, like the fascinus or the mysterious begetter of Servius Tullius. The god's name is related to two infrequently recorded slang words for penis in Latin, mūtō (or muttō) and mūtōnium. "Mutto" was also used as a cognomen, the third of the three elements of a Roman man's name.Lucilius offers the earliest recorded instance of both forms: at laeva lacrimas muttoni absterget amica ("A girlfriend wipes away Mutto's tears — his left hand, that is"), and the derivative mūtōnium. Mūtōnium may have replaced the earlier form, as it appears later among the graffiti of Pompeii.Horace has a dialogue with his muttō: "What do you want? Surely you're not demanding a grand consul's granddaughter as a cunt?" Both Lucilius and Horace thus personify the muttō.Mūtūniātus, used by Martial and in the Corpus Priapeorum, describes a "well-endowed" male.