Dog Penis: What's Normal and Common Problems

What's Normal

• The tip showing when he's excited: this is common and normal, even in neutered dogs. It should go back into the sheath on its own.^2,1
• Two bumps at the base: the bulbus glandis fills with blood during arousal and can look like two lumps. They should go down afterward. Lumps that stay are not normal.¹
• A darker color during an erection: it may look red to purple.¹
• Some licking to keep the area clean¹

Common Penis Problems

Penis stuck out (paraphimosis)

The penis can't slide back into the sheath, often after arousal or mating, sometimes because hair has formed a ring around it. It quickly swells and dries out, and tissue can be permanently damaged.^5,6 On the way to the vet, you can gently rinse it with warm water and apply a water-based lubricant. See a vet even if it goes back in.^6,5

Sheath infection (balanoposthitis)

Inflammation of the penis or sheath causes heavy, often pus-like discharge, licking and discomfort. Causes include bacteria, grass seeds or other foreign bodies, urinary infections and tumors.³

Persistent erection (priapism)

An erection that lasts without sexual arousal can come from spinal problems, medicines or other conditions, and is an emergency if blood flow is cut off.^9,4

Penis that won't come out (phimosis)

A sheath opening that's too small can trap urine and cause infection. It's often found only when a dog tries to mate, and surgery can widen it.¹⁰

Tumors

Transmissible venereal tumors spread between dogs mainly during mating, but also by licking, so they can appear on the nose or in the mouth. They form cauliflower-like growths that bleed easily.^7,11 They're found in dogs in at least 90 countries, mostly where many dogs roam free.¹² Chemotherapy brings complete remission in more than 90% of dogs.¹¹

Blood From a Dog's Penis

Causes include an enlarged or infected prostate, urinary infections, bladder stones, injuries, tumors and clotting disorders. Take him to a vet promptly.^1,4 See blood in dog urine and prostate cancer in dogs.

Care at Home

Keep long hair around the sheath trimmed, and check for grass seeds after walks.^3,6 Apart from a lubricant for a stuck penis on the way to the vet, ask your vet before putting any cream or ointment on the area. Neutering reduces but doesn't stop normal discharge.⁴ See also neutering dogs and reproductive health in dogs.

Frequently Asked Questions

Why is my dog's "red rocket" out?

Usually because he's excited, which is normal if it goes back within minutes. If it stays out or looks dry or swollen, see a vet.

What are the two lumps at the base of my dog's penis?

That's the bulbus glandis, which swells during arousal. Lumps that don't go down need a vet check.

What is a male dog's private area called?

The penis sits inside a sheath called the prepuce, and the testicles are in the scrotum.

Is green discharge from my dog's penis normal?

A small amount of yellowish or slightly green discharge is normal. A large amount, a bad smell or licking is not.

Can neutered dogs get erections?

Yes. It's normal.