Slip Mating Explained: What is its Success Rate?


There are many ways to achieve a successful breeding story. Dogs are pretty intuitive when it comes to the mating process. In a standard setting, they will not even need a breeder’s assistance or guidance. Like in any other species, breeding is something that comes instinctively for most, but it may require a couple tries for inexperienced, young dogs to get it right for the first time.

Whether the female gets nervous and struggles to stay still, or the male cannot seem to find the optimal position to begin the task, all it takes is a little patience and some practice in a safe and calm environment. Before you know it, they will be on the right track to getting to the ultimate goal – having puppies.

What’s the Success Rate of Slip Mating?

When it comes to natural mating, almost everyone is the most familiar with something called a coupling tie or a breeding tie, which is wrongfully considered the only way a female dog can successfully achieve pregnancy. Before we move forward, and to further understand what slip mating is, we need to break down how the breeding tie works. For that purpose, we will need a quick dog anatomy lesson. 

Dog Anatomy 101

Although it shares some basic characteristics with other mammal’s male reproductive organs, the canine penis has a few unique features. For instance, even when not erect, it can remain firm at all times due to a bone called the baculum. Strange as it may sound, this anatomical trait helps the male breed for extended periods. Another significant difference is the presence o the bulbus glandis, commonly known as the ball or the knot, which plays a critical role in achieving the infamous breeding tie. 

Contrary to popular belief, bulbus glandis are not glands, but rather a structure formed of erectile tissue in the shape of a sphere at the very base of the dog penis. This tissue swells with blood and enlarges to its full size at some point during intercourse after the ejaculation occurs, allowing the mentioned breeding tie to happen. 

What Is the Breeding Tie?

Even if you are not a breeder, chances are you have encountered this scene more than once: Two dogs facing opposite directions while apparently being stuck to each other by their rear ends. It may seem the most unnatural and painful position ever, and yet it lasts quite a while. Sounds familiar? This is the breeding tie.

So if you ever come across this seemingly horrific scenario, do not panic. It is perfectly normal in dogs of all sizes and ages during the mating process, and it will go away on its own sometime between 5 to 30 minutes.

No matter what you do, no matter how uncomfortable it may look to you, do not ever attempt to separate dogs that are already locked in this position, since you may cause irreversible damage to their genitals. Keep in mind this happens all the time, and it’s perfectly normal. Everything both dogs will need to get through it is to be left alone to rest and relax. The swelling will go down on its own, and they will be set free to go their separate ways in no time.

Why Does the Breading Tie Happen?

When mating, the male mounts the female from the back and engages in vigorous thrusting for several minutes until the climax. Once ejaculation occurs, and the bulbus glandis fills up with blood and expands about three times its original size, the vulva wraps tightly around it in a lock.

The male will then lift his leg over the female’s back and turn around facing the other way, still attached to her by their hind ends. This way, the male will block the seminal fluid from leaking back and exiting the vaginal cavity, while he keeps on secreting prostatic fluid at the same time.

By pushing the semen deeper, he’s increasing the chances that the sperm will stay inside the female long enough to reach the eggs and allow conception. By the looks of it, the breeding tie seems to be a perfect, bulletproof method, and it is falsely considered to be the only successful form of natural breeding, unlike the dreaded slip mating. However, contrary to popular belief, a tie does not always guarantee that the female will get pregnant. 

What is Slip Mating

Mating without a tie occurs when the male’s bulbus glandis swells outside of the female. Slip mating has also proven to be perfectly normal and does not represent a definitive factor in dogs’ conception problems. Despite being slightly different from what your average mating scene looks like, not achieving a tie does not necessarily mean that mating was unsuccessful and will not produce puppies.

The truth is that pregnancy is still very likely to happen during slip mating. By the time the bulbus glandis swells and the breeding tie occurs, the male has already ejaculated a considerate amount fluid rich in sperm inside of the female’s vaginal cavity.  

Male Ejaculation Stages

The male dog’s ejaculating process consists of three stages: 

  • The first stage involves a pre-ejaculatory fluid, commonly clear, that contains little to no sperm in it.    
  • The second stage is released during vigorous thrusting and contains the most amount of sperm.      
  • The third and last stage occurs during the breeding tie and consists of a clear prostatic fluid that contains an insignificant amount of sperm.   

When the dog mounts off before the second stage of ejaculation, it is called premature withdrawal. In this scenario, you will probably notice the male dog still enlarged and dripping seminal fluid as if a lock had happened. In this particular case, pregnancy is highly unlikely to happen. That is what leads to the misconception that slip mating does not work. In fact, while similar, they are two different scenarios. 

Debunking the Myth

Slip mating happens after the second stage of ejaculation has already taken place. Therefore, it still gives a very high probability of the female getting pregnant despite what breeders may think. When slip mating, even if the breeder considers it a failed attempt, the female should not be taken immediately to another stud since females can conceive and give birth to puppies from different fathers within the same litter. This goes against AKC’s rules and regulations for responsible breeding and is considered highly unethical.


Dog breeding shouldn’t be a stressful process. We must let the dogs follow their instincts and do what naturally comes to them. Even when slip mating might differ from the most known breeding process, it is still fairly common and highly likely to produce a litter.

The real factors that influence the possibility of pregnancy have little to do with whether a tie occurs or not. As long as the male ejaculates inside of the vaginal cavity and the timing is right, there’s no reason slip mating will prevent pregnancy from being achieved.