"Depends on what *kind* of fertility god he was..." Not, apparently, one who would be inclined to gentle love songs and ballads. According to http://www.ukans.edu/history/index/europe/ancient_rome/E/Roman/Texts/secondary/SMIGRA*/Lupercalia.html, the festival got downright gory. Let us know, Pinetop Slim, what happy ditties you come up with to evoke these Luperclian activities... :-)

"The Luperci assembled on the day of the Lupercalia, and sacrificed to the god goats and young dogs, which animals are remarkable for their strong sexual instinct, and thus were appropriate sacrifices to the god of fertility (Plut. Rom. 21; Servius ad Aen. viii.343). Two youths of noble birth were then led to the Luperci, and one of the latter touched their foreheads with a sword dipped in the blood of the victims; other Luperci immediately after wiped off the bloody spots with wool dipped in milk. Hereupon the two youths were obliged to break out into a shout of laughter. This ceremony was probably a symbolical purification of the shepherds. After the sacrifice was over, the Luperci partook of a meal, at which they were plentifully supplied with wine (Val. Max. ii.2.9). They then cut the skins of the goats which they had sacrificed, into pieces; with some of which they covered parts of their body in imitation of the god Lupercus, who was represented half naked and half covered with goat-skin. The other pieces of the skins they cut into thongs, and holding them in their hands they ran through the streets of the city, touching or striking with them all persons whom they met in their way, and especially women, who even used to come forward voluntarily for the purpose, since they believed that this ceremony rendered them fruitful, and procured them an easy delivery in childbearing."