The modification has three variations: the pet can sit, stand, or lie down when the dragonborn scratches it behind the ear. To "activate" a dog, you just need to approach it without weapons or magic.
In the future, the enthusiast is going to add the ability to pet other animals as well. By the way, this mod was released on April 1: “I understand that given the date, this may seem like a joke, but I assure you that it is not. Over the past 10 years we have seen different, ahem, interesting modifications, but there was one key aspect that was always lacking."
You can download the modification here.