Beltane.

Spirituality As The Telegraph reported last year, the Beltane is making a comeback in some cases with a wicker person.  The Goddess and Green Man website has a thorough history of the festival and all its implications:

"Handfasting or not, both young and old went A-Maying... Couples spent the night in the woods and fields, made love and brought back armfuls of the first May or haw thorn blossoms to decorate their homes and barns. Hawthorn was never brought into the home except at Beltane - at other times it was considered unlucky. Young women gathered the dew to wash their faces, made Flower Crowns and May B askets to give as gifts. Everyone was free to enact the Sacred Marriage of Goddess and God, and there was an accepted tradition of Beltane babies arriving nine months later!"