Mounting, thrusting (humping) and masturbation are normal behaviors exhibited by most dogs. Dogs masturbate in various ways. They mount and thrust against other animals, people and objects, such as wadded-up blankets, dog beds and toys. Sometimes, dogs just rub against people or objects (without mounting them), or they lick themselves.
Puppies often mount and hump their littermates, other playmates, people and toys. Some experts believe that this behavior functions as practice for future sexual encounters. As puppies reach sexual maturity, they start to mount other dogs in sexual contexts. After they’re neutered or spayed, many male and female dogs continue to mount and even masturbate because they have learned that the behavior feels good.
Intact (not neutered) males will often masturbate if prevented from approaching a female in heat. Often, during courtship, females in heat mount and hump their male “suitors.” Female dogs also commonly mount and hump other females when one or both are in heat.
Masturbation is part of normal sexual behavior for both altered (spayed or neutered) and intact dogs. Both male and female dogs mount other dogs, people and objects. Most people don’t realize that this behavior isn’t limited to intact male dogs, nor do they know that neutered males can display erections and ejaculate just like intact males. Sexually motivated mounting and masturbation are often accompanied by “flirtatious” body language and courtship behavior (tail up, ears rotated backward, licking, pawing, play bows, etc.).
Sexual behaviors, including mounting and thrusting, are part of normal play behavior. Dogs don’t usually display erections or ejaculate in the context of play. Some poorly socialized or undersocialized dogs excessively mount other dogs in response to play solicitation. They don’t seem to know how to play well and get overaroused during play.
Response to Stress or Excitement
Some dogs respond to stressful or exciting situations by mounting or masturbating. For instance, after meeting a new dog or person, an aroused and excited dog may mount another dog, his owner or a nearby object, like a dog bed or a toy.
Masturbating can become a compulsive habit, especially if a dog does it in response to stress. Compulsions like mounting and masturbating can interfere with a dog’s normal functioning.
Dogs sometimes mount other animals and people to display social status or control. A dog mounting for this reason may or may not display an erection, but he’s unlikely to ejaculate.