What is age of your female dog? Is she in heat? If she is in heat then she can become pregnant. If she is not in heat then humping behavior in dogs is to show their dominance. Sometimes, this humping behavior in male dogs is due to irritation in the urogenital tract cause by infection. If this is case then your male dog needs to be investigated for urinary tract infection. If he is free from any infection then You should keep him away from your female dog. You can also discus this your local vet.
