The hip nudge has been creating awkward moments for dogs and humans for centuries. You know that classic greeting - the one where instead of licking I-love-yous all over your face, your dog turns around and shows you his backside.
It can be a confusing turn of events. After all, you thought this dog was into you. Now, he's giving you the cold buttocks.
Well, it turns out, he is into you.
He's into you so much, you're not just the bee's knees. You're the dog's bollocks.
Getting a hip nudge from a dog - far from being assertive - is the ultimate show of passivity.
"It's reasonable to conclude that when a dog is backing their rear end into you, they don't feel threatened. It shows a sign of safety and comfort - that the dog is trusting of that person," Dr. Ladan Mohammad-Zadeh, a critical care specialist at DoveLewis Animal Hospital, tells The Dodo.
The dog is essentially telling you he's not going to attack. His mouth, along with the teeth that go with it, is as far from you as possible.
"A dog who is coming at you head first with ears back might be uncomfortable or even aggressive, and that is not a situation where you would want to put your hand out for the dog or make it feel threatened in any way," Mohammad-Zadeh explains. "Recognizing these behavioral cues, especially when children or strangers are involved, can be very beneficial for all dog owners. "
There may actually be a couple of other reasons for a dog's rump-first approach.
A dog's posterior, according to Dr. Nadine Znajda, a veterinary dermatologist at BluePearl Veterinary Partners, is a massive source of pheromones - which would explain why dogs are so beguiled by each other's bottoms.
"It's possible your dog may be trying to claim you with his pheromones by backing into you," Znajda tells The Dodo. "They're leaving their scent on you."
Dogs also lean in to their owners as a source of comfort.
"They want to be as close to you as possible," Znajda says. "Some will crawl into your lap if you let them. There are a lot of dogs who are just very bonded with their owners."
Regardless of the reason, you should enjoy this canine version of a bum rush. It comes from a place of love.