This is one of the most common “embarrassing” dog behaviors owners notice, and in most cases it’s completely normal. Dogs gather critical social information from each other’s genital areas, and licking is simply how they process it. That said, persistent or obsessive licking can sometimes point to a health issue in the dog being licked.
How Dogs Read Each Other Through Scent
Dogs have a specialized scent organ called the vomeronasal organ, located inside the nasal cavity and opening into the roof of the mouth behind the upper front teeth. Unlike the regular sense of smell, this organ is wired specifically for chemical communication. Its nerves lead directly to the part of the brain involved in mating and social recognition, and it detects substances that often have no perceptible odor at all.
The genital area is the richest source of these chemical signals on another dog’s body. Urine residue, natural secretions, and pheromones all concentrate there. When your dog licks another dog’s penis, they’re essentially reading a biological profile: the other dog’s sex, reproductive status, health, stress level, and even what they’ve eaten recently. It’s the canine equivalent of reading someone’s name tag and resume at the same time.
This is why genital sniffing and licking spike around intact (unneutered) dogs, females in heat, or dogs that have recently urinated. The chemical signals are freshest and strongest in those moments.
Normal Social Grooming vs. Obsessive Licking
Brief genital investigation, lasting a few seconds to maybe half a minute, falls squarely within normal dog-to-dog interaction. You’ll typically see it during greetings, after one dog urinates, or when two dogs are getting reacquainted after time apart. The dog being licked usually tolerates it or walks away, and the licking dog moves on to something else.
What crosses into concerning territory is when the licking becomes frequent, prolonged, or difficult to interrupt. If your dog repeatedly seeks out the other dog’s genitals throughout the day, ignores attempts to redirect, or the other dog seems irritated or in discomfort, something else may be going on. This pattern can signal either a behavioral compulsion in the licking dog or a medical issue in the dog being licked.
Medical Reasons the Other Dog May Attract Licking
Dogs are remarkably good at detecting illness through scent. If one dog fixates on another’s genital area, it may be picking up on abnormal discharge, infection, or inflammation that you haven’t noticed yet.
Preputial infection (inflammation of the sheath covering the penis) is one of the more common issues. Signs include a yellowish or greenish discharge, redness, swelling, and sometimes a foul smell. A small amount of whitish-yellow discharge from the prepuce is normal in male dogs, but anything that looks thicker, smells off, or appears alongside redness warrants a vet visit.
Urinary tract infections change the chemical composition of urine, which can make the area more “interesting” to another dog. Prostate problems in intact males can also produce unusual discharge. One early sign of prostatic disease is blood-tinged fluid appearing on bedding, along with changes in urination patterns like straining, interrupted streams, or increased frequency. Because prostatic fluid can reflux into the bladder, these issues sometimes get misdiagnosed as simple urinary infections.
If the licking is new, has escalated recently, or the dog being licked seems uncomfortable, check the area yourself. Look for swelling, unusual discharge, redness, or any sores. These findings point toward a veterinary exam rather than a behavioral fix.
When the Licking Dog Has the Problem
Sometimes the issue isn’t medical in the dog being licked but behavioral in the one doing the licking. Some dogs develop compulsive grooming habits directed at other dogs, particularly if they’re under-stimulated, anxious, or haven’t learned appropriate social boundaries. Puppies and adolescent dogs are especially prone to this because they’re still learning canine social norms.
Dogs that were separated from their litter too early sometimes show excessive licking and nursing behaviors directed at other dogs. Similarly, dogs with generalized anxiety may fixate on repetitive behaviors like licking as a self-soothing mechanism, and another dog’s genitals simply happen to be the target.
Risks of Letting It Continue Unchecked
Occasional licking poses no health risk to either dog. Persistent, repeated licking is a different story. The constant moisture and friction on the recipient dog’s skin can break down the skin barrier, leading to irritation, hair loss, and secondary bacterial infections. Damaged hair follicles can develop deep infections with painful inflammation, pustules, and draining sores that require veterinary treatment. The recipient dog may also become stressed or defensive, which can escalate into conflict between the two animals.
How to Manage the Behavior
If you’ve ruled out a medical issue in the dog being licked, the goal is calm, consistent redirection. When the licking starts, use a firm but neutral “no” or “leave it” and immediately offer an alternative activity. A puzzle feeder, a chew toy, or a quick training exercise all work well. Praise your dog when they disengage and shift their attention. Over time, they learn that stopping the behavior leads to something rewarding.
Increasing physical exercise and mental stimulation throughout the day often reduces compulsive behaviors across the board. Dogs that are tired and mentally engaged are far less likely to fixate on repetitive grooming. Extra walks, structured play sessions, and food puzzles can make a noticeable difference within a week or two.
If the behavior persists despite consistent redirection and adequate exercise, or if the licking dog seems genuinely unable to stop, a veterinary behaviorist can help determine whether anxiety or compulsive disorder is driving the behavior and recommend a targeted plan.