Everything You Wanted to Know About Dog Penis Behavior

Here’s everything you want to know but didn’t want to ask about the dog penis — from why the lipsticks come out to dog penis discharge.

dog penis in prepuce
A dog penis in prepuce. Photography courtesy Jessica Pineda.

Living with dogs means living with, or at least ignoring their somewhat gross behaviors. Whether that’s dogs sniffing other dogs’ butts or eating garbage, it’s all a part of parenting canines. A male dog, however, has one behavior that is incredibly embarrassing, especially around polite company. It’s the occasional appearance of his dog penis — or what’s politely referred to as a male dog’s “lipstick” or the “red rocket.”

There’s nothing like having friends and family over and everyone stops talking mid-sentence because a dog penis has appeared. Trust me, I know. My German Shepherd Dog Forest is well known for this.

So what’s up with a boy dog’s you-know-what? Why does it always appear at inappropriate times? And why does your dog have a fascination with other dogs’ private parts? Let’s answer a few of your questions about the dog penis.

Warning — some photos ahead are graphic!


Basic Terminology for the Dog Penis

Since we humans are uncomfortable with saying the “p” word, colloquial terms like “dog lipstick” or “red rocket” are popular substitutes for the term. Those terms describe a dog’s actual penis, which, for the most part, stays in the prepuce. (That’s the furry area you thought was a dog’s penis in more innocent times.)

“Red rocket” or “lipstick” is a pretty apt term: A dog’s erection generally ranges from pink to red in color, and is stiff. Its shape is similar to the top of a rocket or lipstick, hence the nicknames.

Why Does the Dog Penis Come Out?

You probably already know that answer to this, but the dog penis comes out when a dog is aroused.

No, not like that, at least in a non-breeding context. As veterinarian Dr. Eric Barchas explains in his article Why Do Dogs Keep Showing Us Their “Lipsticks”?, arousal is a general term for anything that excites a dog. Arousal can be something as simple as your boy dog getting excited about a training session.

Awkward as it might be to have a dog’s lipstick appear when you’re with friends and family, there’s nothing to worry about according to Susan Newell, owner and lead trainer of Animal Minds Behavior and Training in Rancho Cordova, California. “The best thing you can do is just ignore it and move on,” she says.

A dog penis, aka a dog lipstick or a dog red rocket, can come out for a few different reasons.
A dog penis, aka a dog lipstick or a dog red rocket, can come out for a few different reasons. Photography courtesy Jessica Pineda.

Ignoring it is good, as once the excitement wears off, a dog penis will slip back into the prepuce. By ignoring it, you’re not accidentally rewarding or encouraging your dog’s reaction.

Other Reasons Your Dog May Get Erect: Humping

A male dog, neutered or otherwise, may get erect if he mounts another dog, whether they’re male or female, and starts humping the other dog. This humping behavior is usually innocent in nature. “This isn’t for sexual reasons. They’re not trying to copulate or masturbate,” says Dr. Atif Wardany, the veterinarian and owner of Mobile Pet Hospital of Sacramento, California. “That’s usually play behavior.”

Typically, dogs start humping if they get overly excited or stressed and haven’t learned how to properly channel those feelings. As mentioned, the behavior itself is innocent, and if the other dog doesn’t like it, they’ll tell your dog. However, that kind of behavior is embarrassing or offensive to lots of people, so if your dog is known for humping, train your dog not to hump other dogs.

Other Reasons Your Dog May Get Erect: Mating

One of the other times a dog penis makes an appearance is if a female dog in heat allows an intact male dog to mount her. (For most of us, since we typically spay and neuter our dogs, we’ll never see that.) This is also the time when a dog’s penis does something unique.

“A dog’s penis has a bone in it, and in the middle of the bone there is a gland inside it that swells up when the male’s copulating,” Dr. Wardany explains. “The purpose is to keep the penis inside the female.”

Once that happens, the dogs are stuck together for a short period of time until the swelling goes down. This is often referred to as a male dog “tying” a female.

What To Do If Your Dog’s Penis Has Discharge

Every now and then, you might see yellowish-greenish discharge or pus coming out of your dog’s prepuce. According to MyPetsDoctor.com, that discharge is a mix of cells and lubricant that keeps the dog penis protected while in the prepuce. You shouldn’t see this discharge all that often and only in small amounts.

However, if you are seeing a lot of discharge and it’s accompanied by your dog licking his privates excessively, it may indicate a serious health problem such as a urinary tract infection or canine cancer. And if the blood is mixed with the discharge, that’s a signal to get your boy to a veterinarian ASAP.

Can Neutered Dogs Still Get Erect?

The short answer? Yes. A neutered dog can’t get a female dog pregnant, but since dog arousal isn’t always tied to sexual situations, the notorious dog penis can and will make an appearance.

Why Do Dogs Lick Other Dogs’ Privates?

It’s bad enough you’ll sometimes have a male dog exposing his dog penis for everyone to see. If you’re like me, and you have two dogs, one who happens to be a spayed female, you’ll have the added joy of your dog deciding it’s a great time to starting licking your other dog’s private parts. My sister’s family has got to experience this on several occasions, much to my utter mortification.

So, why do dogs do this? It’s actually fairly normal for male and female dogs to sniff other dogs’ butts, and that sometimes involves licking, too. “The science isn’t entirely clear on what dogs get out of smelling/licking each other in the private area,” Newell says. “However, the theory is the dog can learn the [other dog’s] sex and if they are sexually receptive by doing so.”

Dogs smelling and licking each other’s private areas is perfectly normal dog-on-dog interaction; however, there’s always one or two dogs that seemingly go overboard and won’t put their noses or tongues away. This can lead to uncomfortable situations between pet parents, some who might not understand what is going on. You’ll have to talk to the other owner to determine his or her comfort level with what’s happening.

“Some dog owners are of the mind that they should let the dogs sort it out. The other dog will tell the other dog when they’ve had enough of smelling and licking,” Newell says. “Other times, it’s best to call your dog away if he spends too much time with the other dog.”

So there you have it: Your guide to everything dog penis related. You may now pretend you never read this article.

Thumbnail: Photography by Kryder17/Thinkstock. 

This piece was originally published in 2017. 

Read more related articles on Dogster.com:

48 thoughts on “Everything You Wanted to Know About Dog Penis Behavior”

  1. I have 4 months pom & this was first time I saw his entire red rocket out & I was wow!! I kinda scared to see that in his age lol..
    Thank you though

  2. My Dog Is Embarrasing

    wow, my first research on the 'matter'…my bro in law calls in the little red demon. well anyway when our house dog was entertaining a female dog in heat we realized there is nothing small about the 'little red demon'. wow, we were so naive.

  3. So I was petting my dog, and I noticed something weird sticking out of his area and I searched it up and it said that he had an erection. My mom then said that maybe it was because I was giving him attention because we have our attention on my guinea pigs most of the time. And he’s getting really old.

  4. I have a 10mth old pitbull and we have never seen his lipstick. He hump the laundry when we are sorting our clothes, and nothing is this something we should be worried about?

  5. Sửa Chữa Máy Lọc Nước Kangaroo Tại Nhà

    Đây thật là một thông tin hữu ích. Cảm ơn bạn rất nhiều

  6. Thay Lõi Tại Nhà

    cảm ơn bạn rất nhiều vì đã đầu tư vào bài viết đó. Tôi thấy đây là một bài viết thực sự hữu ích và thú vị để đọc!

  7. Thank you for this entertaining article. I have a 6 month old, male husky-shep mix. I wanted a girl, but hubby insisted on a boy. Oh the joys of the “pinky”. – It’s out All. The. Time. He looks at the cat – boing! He gets fed – boing! We grab the leash – boing! Question (because it’s been 20 years since I’ve had a male dog), does it lessen when he is fixed? Do you think it is more apparent in some breeds more than others (shepherds?) We will be neutering him as he gets closer to a year old for developmental reasons. Ugh. And thanks!

    1. I has two Shepherds and they would have theirs out a lot, one would be hard sticking out as he walked around like nothing to it. The other was not as bad, but sitting down, every time it would stick out. My Malamute will get hard and stick out. Had another Husky mix fixed that would stick out a lot when he sits. The other dogs I talked about were not fixed. My other husky that is fixed his sticks out a lot when he sits. They all tend to mount and hump one another all the time, every day thing for them, and the Huskies are all fixed.

  8. Thank you for this entertaining article. I have a 6 month old, male husky-shep mix. I wanted a girl, but hubby insisted on a boy. Oh the joys of the “pinky”. – It’s out All. The. Time. He looks at the cat – boing! He gets fed – boing! We grab the leash – boing! Question (because it’s been 20 years since I’ve had a male dog), does it lessen when he is fixed? Is it more apparent in some breeds more than others? We will be neutering him as he gets closer to a year old for developmental reasons. Ugh. And thanks!

  9. my dog is always licking his lipstick in the night , never had this before with any of my dogs always had males, he is a year old

    1. Sharon, did you ever figure out what was going on with your dog? I have a 5 year old dog that just recently started doing this and also seems to be having some pain when lipstick starts to come out

      1. If you dog appears to be having pain I would recommend you see a vet. If you cant afford it, contact local animal society.

  10. It seems weird to me that people even ask any questions on this site. Every answer I’ve read says ” thanks for reaching out. We suggest contacting your vet.” if I could afford to ask the vet a question I sure wouldn’t be looking online for an answer. If it is not life threating or a yearly exam of course take them in.but just to ask a question is awfully expensive. Why isn’t there web sites that can answer questions for us instead of just telling us to see our vet?d

    1. Hi there,
      Thanks for this. We provide as much advice and insight as possible, but all serious health situations are different and need to be seen in person by a vet professional.

    2. If you read the comments they also provide you with possibilities but have to put that so people understand it’s only a possibility not a diagnosis smh ?‍♂️

  11. Tamirose Ferchak

    My male dachshund never exposed his lipstick until I recently rescued a female dog and she went into heat within 10 days of me taking her into my home. Then he began to share his lipstick and tried to hump her & she clearly let him know to “back off” and wouldn’t tolerate his games….Ever since that happened his external genitalia has changed …..it used to point forward (his little rocket launcher is what I call it) and was perpendicular to his body – face forward all the time. Lately, over the past few months I’ve noticed that it appears to be much smaller in size and pointing downward instead. I’ve never had a male dog where their genitals were exposed 24/7 (had Papillons before so the hair/fur covered all of that up) – could he be having an issue with his male genitals (he IS neutered) or a hernia issue? I’ve never heard of a dog having a hernia but it’s the only thing I can think of as to what internally could cause a distortion/alignment change in his external appearance. Looking forward to some feedback from all the male dog knowledge/experts. Many thanks.

    1. Hi there,
      Thanks for reaching out! We suggest contacting a vet with this question. Your dog might be suffering from this condition: https://qa.dogster.com/dog-health-care/dog-lipsticks-and-dog-paraphimosis

  12. My 8month old Labrador has been bleeding since a week ago and he is also been licking his privates excessively . I tried to consult the vet but the people out there is quite unprofessional(cant risk my boy)so can you help me out with home remedies or with some medic prescription?

    1. Hi there,
      We suggest contacting a vet ASAP. If you don’t like your vet, we suggest researching other options. Hope your dog feels better!

  13. “The science isn’t entirely clear on what dogs get out of smelling/licking each other in the private area,”

    This is so false. They get TONS of information from the genitals of other dogs…

    1. Hi Matt,

      Thanks for reading! Let us know if you have any specific information / links we could add to this piece to change this statement.

  14. My sister had a dog that had this same issue. The dog would hump mid air when excited and the full erection would show itself. The liquid he released was semen. She took him and got him neutered and the problem disappeared.

  15. I agree with Mavis. I would go see a doctor just to be safe. A lot of the time a dog can detect something abnormal in our bodies and if he is concentrating on that one area you might have something or nothing.

  16. I hope I can get a response . I’m concerned this morning my dog jumps off the bed starts sniffing and coming up to the side of the bed I’ve not been feeling to good, but I noticed his Willie was out and never went back in. Now he is adopted but I was told he was neutered . I’m a bit concerned and need your advise he’s been trying to lay on my breast and trying to put his head under my shirt etc and it’s crepping me out . I may need to give him back . First time dog owner and I do t know what to do !

  17. My dog gets excited, grows ‘double balls’. The two he already has & then seemingly another 2 above that in the shaft. Then he starts squirting liquid in multiple drops. Is this pee or is this him ‘releasing’ different liquid? Would it stop if I got him neutered ?

    1. Michaela Conlon

      Hi Amy,

      Thanks for reaching out! Here are two articles that provide more information about dog genitalia:


      We suggest contacting your vet with specific questions related to your dog and whether neutering him would change this.

  18. My jack Russell is 13 years old and his Willie when its out has gone white before it was always pink/red does he have a problem that I need to take him to see the vets

    1. Hi Kirsten,
      We would definitely contact your vet to see if you need to take your dog in. Best of luck and hope your dog feels better!

    2. I had never seen my dogs.and I have a small dog are big dog or small dog do they have different lipsticks like big ones or small ones

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