This morning while running our dog around the dog park, she took to playing with an same-sized pup named Evie. She’s a shepard mix of some sort who loves to run and growl and tumble with Lucy, our pit/border/beagle/boxer mix.

I don’t let Lucy pick up sticks or balls or ropes much at the dog park because she quickly becomes possessive. But today, the dogs collectively gathered so much detritus from the ground I gave up. Then one of them dropped a piece of rope near my feet and I picked it up and ran.

That’s when Evie ran after me and chomped on my butt. It wasn’t hard. No more threatening that what she does with Lucy. Dogs love to gnarl on each other and Evie simply applied Dog Rules to my glutes. I stopped, laughed and looked back at the other adults watching the dog circus. We all chuckled. Lesson learned, I thought.

Not all dog chomps are so playful or benign. Many years back I was running on a path that passes through Island Park in Geneva, Illinois. Suddenly I felt a painful bite on my left butt cheek and swung around to find a collie standing there with its teeth bared.

Normally I don’t think of collies as an aggressive breed. But sure enough, this one bit me in the ass. I stood there rubbing my butt when the owner yelled at me. “What are you doing running on the trail?”

“It’s a running path,” I replied, a bit flabbergasted at the question. “People run on it.”

“Well, you scared my dog,” he barked back.

“Your dog should be on a leash,” I replied. “Those are the rules in this park.”

The owner stomped over and collected his dog. I continued my run and checked my butt cheek when I got home. Sure enough, there were reddish blue teeth marks on my little white ass.

I’ve been run over by dogs. Snapped at by dogs. Barked at by dogs of many kinds. But none surprised me so much as that collie on the running path that day.

Some people just don’t get it when it comes to their dogs. I like to think I do, but not always. I make mistakes in interactions with dogs and assume some are more friendly than they really are. Dogs have their own rules. And unless you’re a dog, and not a runner, you probably don’t understand them in the moment.