where does a male dog enter a female dog
Canine reproduction Male canines are the only animals that have a locking bulbus glandis or "bulb", a spherical area of erectile tissue at the base of the penis. During copulation, and only after the male's penis is fully inside the female's vagina, the bulbus glandis becomes engorged with blood.[9] In coyotes, when the female's vagina subsequently contracts, the penis becomes locked inside the female.[10] This is known as "tying" or "knotting". While characteristic of mating in most canids, the copulatory tie has been reported to be absent[11] or very brief (less than one minute)[12] in the African wild dog, possibly due to the abundance of large predators in its environment.[13]