The first-time dog breeder is often shocked and worried to find that the pair of dogs have become locked together during the mating process and don't appear capable of separating. This is a unique feature of dog mating that is known as the “tie.” It is often regarded as the sign of a successful mating by experienced breeders, and although it is not necessary for a successful pregnancy it has a revered and almost mystical status.
When dogs mate, the male mounts the female from behind. When he enters her, the bulbis glandis of his penis swells inside her and is held firmly by the muscles of her vagina. When he finishes thrusting, the penis can not be withdrawn. This is the “tie.” The male will then normally slide a hind leg over the female's back so they are facing away from each other, with their rumps together.
During the tie
A tie normally lasts from two to 45 minutes. Sperm is generally released by the male at the start of the tie while secretory fluids continue to be released for quite some time. After the male dog turns, an inexperienced female will often squirm around in discomfort and vocalise her distress. Male dogs tend to be calmer and normally stand and wait until the penis is suddenly released.
Calming and supervision
When the dogs are tied, the best thing you can do is to get down on the floor and calm them. If the female moves around too much she can damage the male so you should pat her and talk to her to keep her calm. Never try and force them apart as this can damage them both. If the tie lasts for over an hour then you should get veterinary advice.
Spend time with the female and keep her moving and occupied so that she does not try and urinate for 15 minutes after separation. Walk the male until he has no erection and his penis has returned inside the sheath. It can sometimes be held by matted hair, and using a little Vaseline or KY jelly can help it to fully retract and get things back to normal.