Today's Myth Monday looks at information on the Bona Dea, from a 1992 article, The Festival for Bona Dea and the Thesmophoria," by H. S. Versnel (Greece & Rome, 1992). The Bona Dea festival honors Faunus' wife.
There are two basic, related stories told of her. Faunus beats the wine-intoxicated Bona Dea with myrtle, a plant associated with the love goddess. Culpability varies depending on the writer, as does the status of Bona Dea as matron or virgin.
One version appears in Plutarch's Roman Questions (20).
Faunus in Plutarch is a mortal seer. The Christian Lactantius (c. A.D. 250 -c. 325) tells a similar story, but has Faunus regret his actions:20 Why is it that the women, when they adorn in their houses a shrine to the women's goddess, whom they call Bona Dea, bring in no myrtle, although they are very eager to make use of all manner of growing and blooming plants?
Was this goddess, as the mythologists relate, the wife of the seer Faunus; and was she secretly addicted to wine, but did not escape detection and was beaten by her husband with myrtle rods, and is this the reason why they do not bring in myrtle and, when they make libations of wine to her, call it milk?
Or is it because they remain pure from many things, particularly from venery, when they perform this holy service? For they not only exclude their husbands, but they also drive everything male out of the house whenever they conduct the customary ceremonies in honour of the goddess. So, because the myrtle is sacred to Venus, they religiously exclude it. For she whom they now call Venus Murcia, in ancient days, it seems, they styled Myrtia.
But as Pompilius was the institutor of foolish superstitions among the Romans, so also, before Pompilius, Faunus was in Latium, who both established impious rites to his grandfather Saturnus, and honoured his father Picus with a place among the gods, and consecrated his sister Fatua Fauna, who was also his wife; who, as Gabius Bassus relates, was called Fatua because she had been in the habit of foretelling their fates to women, as Faunus did to men. And Varro writes that she was a woman of such great modesty, that, as long as she lived, no male except her husband saw her or heard her name. On this account women sacrifice to her in secret, and call her the Good Goddess. And Sextus Claudius, in that book which he wrote in Greek, relates that it was the wife of Faunus who, because, contrary to the practice and honour of kings, she had drunk a jar of wine, and had become intoxicated, was beaten to death by her husband with myrtle rods. But afterwards, when he was sorry for what he had done, and was unable to endure his regret for her, he paid her divine honours.A different story comes from Macrobius (A.D. 395 - 423), our principal source on the Saturnalia, another December festival. Macrobius Sat. 1.12.20-29 says Bona Dea is another name for Fauna, Fatua, or Ops, and a daughter of the god Faunus who wishes to commit incest with her. He makes her drunk on wine, but she still won't submit to his advances, so he beats her with myrtle twigs, again, to no avail. Eventually, Faunus has his way, but only after turning himself into a snake.
Lactantius The Divine Institutes
The Bona Dea Festival was held in Rome by Vestal Virgins and sexually active matrons, with plants, but no myrtle, and with wine, but wine that was referred to as milk, and its container as a honey pot. There is one additional twist in the components of the Bona Dea Festival, but first, the background:
There was an early Roman prohibition against matrons drinking wine and a well-known tale of Romulus exonerating a husband for beating his wife to death for violating this law. Early Romans believed the problem with women drinking wine was that it led them to uncontrollable passion, and from that to adultery, a capital offense. By a leap in logic or something, the law counted the drinking as wrong as adultery.
"Other offences, however, were judged by her relations together with her husband; among them was adultery, or where it was found she had drunk wine -- a thing which the Greeks would look upon as the least of all faults. For Romulus permitted them to punish both these acts with death, as being the gravest offences women could be guilty of, since he looked upon adultery as the source of reckless folly, and drunkenness as the source of adultery."The last component was that women who might well be drinking the intoxicating beverage at the event and becoming lusty, were prevented from acting on their desires because all males were forbidden at the Bona Dea Festival. Clodius' presence created a chink in the armor.
Dionysius of Halicarnassus (fl. 1st C. B.C.) 2.25.6
* There is already much material on this site on the topic of mythology (especially, Gods and Goddesses and The Stories of the Ancient Greeks). In Myth Mondays I attempt to bring up an element of mythology that is either timely or less well known.

Comments
I first learned about Bona Dea in the Masters of Rome series. Thanks for shedding light on the details.