of monstrous couplings (which he called spintriae), so that, intertwining themselves and forming a triple chain (triplici serie connexi), they mutually prostituted themselves in front of him to fire up his flagging desires. Most threesomes depict two men penetrating a woman. A medallion from Roman Gaul shows two men reclining on a bed, one on the right and one on the left, with their legs extended under a woman between them. Another shows a woman "riding" a man who reclines, while a man standing behind her parts her legs to enter. A far less common variation has one man entering a woman from the rear while he in turn receives anal sex from a man standing behind him, a scenario found in Catullus, Carmen 56 as well as art. Catullus makes it clear that this concatenation was considered humorous, possibly because the man in the center could be a cinaedus, a male who liked to receive anal sex but who was also considered seductive to women. Foursomes also appear in Roman art, typically with two women and two men, sometimes in same-sex pairings. One example of a foursome from the Suburban Baths at Pompeii demonstrates what Romans saw as the superior role. A woman on the far right kneels beside a bed to perform cunnilingus on a woman lying on it; this woman in turn fellates a man who kneels above her. The man is himself receiving anal sex from a fourth figure, who is represented as the "victor": he acts only to fulfill his own sexual gratification without providing it to others, and looks directly at the viewer with a triumphant wave of the hand. A Latin epigram by the Gallo-Roman poet Ausonius (4th century AD) is a riddle that depends on familiarity with the configurations of group sex: "Three men in bed together: two are committing debauchery (stuprum), two are being debauched.""Doesn't that make four men?""You're mistaken: the man on either end each counts as a single offense, but the one in the middle both acts and is acted on." Masturbation Masturbation is little noted in the sources for Roman sexuality. The Romans evidently preferred the left hand for masturbation. Martial has a few mentions in his poems, but considers it an inferior form of sexual release resorted to by slaves, though he admits to masturbating when a beautiful slave-boy is too expensive to obtain: "my hand relieved