(Also Cotytto, Kotys, Cottyto)
Cotys was a Thracian (also Phrygian) goddess of the moon and sexuality. She was also associated with fertility, debauchery and immodesty. She was the mother of the hundred-handed giant Cottus, who represented her collegium of fifty priests or "spiritual sons". Her worship was accepted in Corinth in 425 BC, and she began to be secretly worshipped in Athens around the same time. The worship of Cotys was eventually accepted in Athens. She was represented either as a hunter goddess or a mother goddess. Her worship in Greece and Sicily persisted long enough to be classified as witchcraft by the Christian church, who also went so far to label Cotys a demon. She may have been a manifestation of Proserpine or Ceres.
Her servants were called the baptai or baptes (from the Greek verb 'to wash' but meaning 'baptized ones'). They would celebrate secret licentious festivals involving baptism in honor of the goddess. Orgies were held at night to release life through the celebration of the erotic. The male worshippers of the goddess would dress in women’s clothing or, according to some sources, castrate themselves. The priests spoke in a made-up obscene language and would wash themselves in an effeminate manner. The celebrations and rites, called Cotyttia, undertaken by the worshippers of Cotys were said to be so obscene that they disgusted the goddess herself.
Aeschylus wrote 'O adorable Cotys among the Edonians, and ye who hold mountain-ranging instruments;' which began a discourse on the use of music instrumentation in worship.
Theocritus called her 'the crone, Cottytaris, that piped of yore to the reapers in Hippocoon's field.'
She is mentioned in Comus by John Milton in the lines:
Com let us our rights begin,
'Tis onely day-light that makes Sin
Which these dun shades will ne're report.
Hail Goddesse of Nocturnal sport
Dark vaild Cotytto, t' whom the secret flame
Of mid-night Torches burns; mysterious Dame
Sources:
http://www.theoi.com/Kronos/Bendis.html
http://www.oscoda.net/bluemoon/c-goddess.html