The Horse Market SF is a private event for all male identified persons that takes place each month all over the U.S. but mainly San Francisco where I live. It is modeled as close as possible to the famous Fickstutenmarkt party that is held in Europe. This to some people, is known as the Stallion and Mare party.
Here, willing Mares (a bottom) offer themselves to stallions (a top) without ever seeing their faces.
And just like the Fickstutenmarkt event, there are strict rules and laws that need to be followed. (see Rules page)
Before the event begins, every participant has to decide whether he wants to attend as a Mare (bottom) or as a stallion (top) and there are no changes.
(It is not possible to change roles once the market begins!)
On the day of the market, the Mares arrive and undress either to underwear or naked and then get hooded.
After they are ready, the Stallions enter and can fully inspect the Mares at their leisure.
When a Stallion has decided on a mare, he can then mount the Mare.
When the Stallion has finished mounting the mare, they are then available for mounting by other Stallions.
Note: This party is not affiliated with the Fickstutenmarkt party in Europe. I have attended their party in Berlin a couple times and love it so much I'm starting it here. I've spoken with them about my party and they have no problem with me starting the same kind of event in the US.