Like much of erotic play and roleplay, animal roleplay in an erotic or relational context is entirely defined by the people involved and by their mood and interests at the time of play. It ranges from the simple imitation of a vocal "whinnying" of a horse to the barking, panting or playful nudging of a puppy, or playful behavior of a kitten, to crawling around on all fours and being fed, or petted, by hand. To the greater extremes of dressing up as a pony in modified horse tack, masks, prosthetics and temporary bondage based body modification (such as binding the forearms to the upper arms and/or the calves to the thighs).
Public participation in human-animal roleplay is varied. A couple could inconspicuously role-play a pet play scene in public, which would look to the casual observer like one partner is merely stroking the other's neck. In the case of some BDSM fetishists, one partner may wear a dog collar with a leash attached.
The reasons for playing such a character or animal can vary as much as the physical manifestations and intensity of the play. Some people enjoy being able to "cut loose" into a different, or more dynamic personality. In some cases, pet play is seen as a loving, quiet cuddling time where there is no need for verbalizations and the simple act of stroking, rubbing and holding the other partner is satisfying or reassuring in and of itself for those involved. For others, there may be a spiritual side to it. Some feel closer to their animal totem, while others may identify with something akin to a deeper side or part of their psyche (known as therianthropy). There is generally the experience of power exchange set up in a context or structure which they can accept.
Some cases could be considered a type of animal transformation fantasy. They can have strong elements of exhibitionism, be enjoyed in the privacy of the home, or lie somewhere between either boundary. While not widespread, erotic human-animal roleplay is still enjoyed by a sizable number of people. However, it is still primarily identified with BDSM practice. Though commonly misinterpreted as being associated with furry or other alternative lifestyle activities, that is generally not the case though some instances may exist.
For most participants, it has no connection whatsoever with bestiality, which is controversial and would usually be considered edgeplay in BDSM circles.
Autozoophilia is sexual arousal that depends on acting out or imagining one's self as an animal. Paraphilic interests that involve being in another form have been referred to as erotic target location errors (ETLEs), and autozoophilia would represent an autoerotic form of zoophilia. Autozoophilia is mostly practiced by wearing an animal costume, such as a latex mask, mascot costume or fursuit.
Each type of play can focus on a certain "strength" of an animal character. Ponyplay often involves the practice and training that a horse owner or trainer would put their horse through to learn how to walk, canter, etc., as modified for human limbs. Puppy and kitten play often can involve BDSM related discipline. Cow Play often involves fantasies of lactation and impregnation. The usual limits of safe, sane and consensual apply to roleplay as much as any other activity between humans who accept and respect their partner's interests and limits. For most, this does not include bestiality.
Note: Just because one partner is playing the "pet" does not necessarily make them the passive or submissive play partner in the scene.
Some people believe that they have certain animal 'instincts' and through animal-roleplay can let them out. This is especially true in the BDSM communities, where some people 'live' as their chosen animal 24/7. This type of mentality goes beyond roleplay and becomes a full lifestyle for the parties involved. There are also 'hybrids'. These are humans who live part-time as one type of animal, and part-time as another. This is usually determined by the situation.
In the BDSM scene, people engage in animal roleplay to build stronger emotional connections. People develop deep emotional connections with their pets. Petplay, especially pup and kitten play seeks to create the same deep emotional connection between the owner/master and submissive/pet. The Domme may demand unconditional love and obedience, but they may also train their pet to be more emotionally perceptive and empathic. This helps the sub feel safe and secure in the relationship.