I have to agree with smash. I dont see a problem with using a serving stallion to tease the mare, but only if he is getting that mare. I would not use another stallion to tease the mare if the serving stallion can see it. Frustrated stallions can easily end up out of control, regardless of how experienced the handler is. I have also seen stallions hit fences, trying to get to the mare when he can see her being teased by another.