Why Do Dogs Show You Their Bum

Your dog might sit on your feet, back up into your leg, or spin in excitement until their rear is closest to you. And sometimes, when you expect a happy slurp in greeting, you might get a face full of dog butt instead.
A dog’s butt is so much more complex, both physiologically and socially, than a human’s. You probably know that dogs sniff each other’s rear ends to get acquainted, but what else goes on beneath the tail? Why do they turn around and give you their rear instead of their face? Is this normal behavior? Why do they think we want their back end instead of their front?

Dogs sniff each other’s rears as part of their introduction. It’s an important way that dogs get information about each other. Humans might think it’s strange or awkward, but for a dog, a routine sniff beneath the tail is more effective than shaking hands and saying “hello.”
Because of scent glands under their tails, a dog can sniff out all kinds of information, including what the dog eats, their general health, mood, sex, age, how much they exercise, and even stress level. Additionally, this “rear-first” method of introduction can sometimes stave off a conflict, as it avoids direct eye contact which leads to assessing dominance between the two dogs. Since greeting others in this manner is natural for dogs, sometimes they assume that humans feel the same way.
The other common behavior dogs will demonstrate is something usually called the “hip nudge.” A dog presenting their rear to you is a sign of passivity and friendliness. Turning their face away demonstrates that they trust you and don’t feel threatened. A dog will either touch you gently with their hip or bum, or will wait passively with their backs to you. A dog that isn’t comfortable with you won’t turn their backs and show this form of vulnerability. They’re showing that their teeth are furthest away from you and don’t intend to harm you.
Another possible, related reason why dogs present their rumps to you is attempting to “claim” you. Since those scent glands under their tails are a massive source of pheromones, chemical smells that we humans don’t notice, they may be trying to leave their scents on you, therefore claiming you as theirs. Which is totally normal. Dogs just want to show you how much they love you and be close to you.
One other simple reason: they just want a good scratch. Dogs who have been affected by fleas may have a particular spot, just above the base of the tail on their backs, where the itchy sensation becomes localized. Even if they don’t have fleas, that spot is a common favorite in a lot of dogs.

Your dog’s rear-first greeting is completely normal and acceptable. Don’t be offended if your dog would much rather sit on your foot than lick your face. Even if they might seem a little pushy or persistent with their rumps, it doesn’t mean your dog is trying to control you or dominate you. Actually, the reverse is true: you dog is showing you passivity. A dog presenting their rear is communicating that they trust you not to harm them, and that they, in turn, won’t harm you. It’s a gesture made out of love, friendliness, and trust.
If your dog is really persistent—or really big—and their hip bumps are actually knocking you or your kids over, don’t punish them for their hip nudges. They don’t realize their loving greeting can hurt anyone. Instead, give them the affection and attention in greeting (like a good scratch above the tail) before they can knock into you, and distract them with a toy or something else. You can also consult a trainer to work on training your dog to sit and calm down for a few minutes when you first greet them at the door, so their excited backside bumps don’t result in any accidental knockdowns.

Since dogs only want to show you love and passivity by showing you their rears, there’s nothing about showing you their rear that should be considered concerning. You may feel differently if you’ve ever been awoken by a dog sitting on your head, but they don’t mean any harm by it. If you have a large dog and small children, you may need to work with your dog to avoid overexuberance-caused accidents, but don’t punish your dog for their hip nudges. It would be like yelling at someone for saying “I love you.”
If your dog has demonstrated other behaviors, like rubbing their bum on the carpet or grass, you may need to consult a vet to rule out parasites or other conditions that may be affecting them. 

A dog’s rear end is a complex body part, used not only for expelling waste and occasionally gas, but also for introductions, pheromones, and demonstrating their love and their trust for you. So, if you have a dog who loves butting in, give them a scratch and a pet. They love you!