A prolonged tie is one that lasts for an hour or longer. The problem is caused by a spasm of the constricting vulvar ring. The ring maintains the dog’s erection by preventing the blood from leaving the bulbus glandis and returning to the body. Eventually the animals become frustrated and begin to tug against each other, aggravating the problem.
Do not throw water on the dogs or try to pull them apart. Instead, turn the male so that he mounts the female and then push on his rump to increase the depth of penetration. This relieves the constricting effect of the vulvar ring on the penis and allows the bulb to subside.