If you freak out every time you spot your precious dog enthusiastically humping a stuffed animal, don't. Remember that dogs simply don't follow the same social norms that human beings do. The humping of random items -- and peoples' legs -- is usually a totally normal and healthy canine behavior.
Things That Dogs Hump
If your dog humps stuffed animals, he's probably not targeting them specifically -- they just happen to be there. Canines mount a lot of random items, whether limbs of human beings, legs of chairs or anything else they can find. You may even notice your dog trying to hump other living things -- perhaps even your poor, unsuspecting household cat.
Sexual Humping
Humping is often a normal doggie reaction to burgeoning sexuality and racing hormones. If a dog is sexually mature, humping is no surprise -- in either gender. Although mature male canines can hump things at essentially any time, the behavior is more common in female dogs who are in the middle of their estrus cycles. Neutering and spaying surgeries often get rid of humping behaviors, especially when they're performed on animals who have not yet gone through "puberty."
Emotionally Overwhelmed
Not only is humping a normal part of canine sexuality, it also is a normal reaction to immense emotional ups and downs. If the movers are at your house and everything is going out in a cardboard box, your poor and confused pooch may manage the frustration and confusion by -- you guessed it -- humping the unpacked stuffed animal lying on the floor. If his poodle "girlfriend" Fifi is visiting and brought along another canine pal, your excited doggie may react by humping, too. Humping is often how dogs respond to brand new, roller coaster emotional experiences -- both good and bad. If a dog has a tendency to hump when nervous and confused, the behavior is not too dissimilar from human anxiety management behaviors. If you have a habit of smoothing your clothes out obsessively when you're nervous, then you know a bit about how your pet feels.
Time to Play
If your dog is in play mode, he may express his thrilled feelings by humping things -- whether stuffed animals, other doggies or any other toys within his reach. Humping during playtime is often just a classic sign of canine playing, not unlike lunging and pouncing.
Medical
Although humping stuffed animals is, for the most part, normal and no reason for alarm, it occasionally can point to health issues in canines. For example, if your dog is intensely itchy, he may resort to humping stuffed animals as a means of relieving the irritating feelings. Intense itchiness is often a symptom of skin allergies. Apart from allergies, health-related humping may also arise from hormonal medical conditions. If your dog's stuffed animal humping seems excessive, consider the possibility that it is medical and beyond his control -- then call your veterinarian immediately. Never assume that something is normal just because other dogs do it too.