It is not a fertility festival. Not all pagan religious observances are fertility related. Pagan is not a synonym for nymphomaniac.
YOU ARE AN UNEDUCATED AND PRESUMPTIVE ASSHOLE.
I’m really sick of the assumption that everything pagan is about sex all the time.
The pagan winter solstice celebrations are near uniformly about the return of light and warmth to the world. They often celebrate the birth/rebirth/return-to-power of a sun or light god. In Celtic tradition, the victory of the Oak King over the Holly King. In Roman tradition there is a a focus on a god of agriculture and in the subset of Mithraism, a light/sun god. Celebrations typically include feasts, burning symbology (yule logs etc), decorating with evergreens to indicate the return of greenery to the land, and some gift exchange.
You want a fertility rite, check back around spring.
If you don’t have any fucking clue what you’re talking about, PLEASE SHUT UP.