I think it is a celebration of the earth's fecundity and the fact that it's roots lie in an act of act of mischief and impropiety.

The horns are the horns of the cuckold. Referred to in Shakespeare, and as Evelyn Waugh put it in Brideshead Revisited, "My cuckold's horns made me Lord of the Forest."

I bet thats why the Abbotts Bromley dancers have stags antlers when they dance.

A hymn to licentiousness and fornication.