Nature is truly amazing! Nature has made a way to ensure that impregnation will occur in canine reproduction. If you have never seen mating dogs, you probably would worry that your beloved pet will be harmed because some of them would whine and appear to be hurt while staying stuck together end to end. Helping the dog by separating them could do more harm than good.
When canine copulates, the male dog would mount the female from behind. A cooperative and receptive female would move its tail to the side and allow the male to get a good hold. This is called flagging. The act of reproduction in canines is a lot different from humans. A dog’s penis is not erect when it enters the bitch’s vagina. Penetration is achieved because a small bone inside the penis called baculum holds the penis rigid.
Once penetration is achieved, the bulbus glandis, an erectile tissue situated at the base of the penis swells with blood and traps the penis inside the bitch’s vagi