How do you keep a stallion from going crazy with mares around?

at twelve years old gelding may or may not help. He can still exhibit stallion like behavior because of the age gelded. He needs a job, and worked. Mares/stallions can smell each other from ten miles away, so mare/stallion being close to each other isn't the problem. Give him a job, work him, tie him in the corner of his stall if his behavior is not acceptable, this works for mine. Of course, do not turn him out with a shared fence, that will only aggravate it, and don't turn him out with the mares. The vicks is a good idea, you can also get him a shot from the vet if you are not going to be using him for breeding. Talk to your vet and stable manager about your options.