This is an image I only found about recently during my gameplay, it has come to my attention that not everyone knows how to pet the dog.
So this is a full tutorial on how the dog works, its functions and why it should be praised as such

Well okay...
But how do I pet the dog?
Its simple actually! it requires 4 steps

• First Step
  boot up the game on your device
  However, in case you dont know how to do that, here is a guide to that:
  https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=3088454915
  
• Second Step
  Now that you are in the game, you are presented with the starting cutscene, once it finishes, you are going to be presented with THIS animated image!
  What you are going to do, is to press the "Play" button on the screen, by moving your mouse towards it
  
  
• Third Step
  Now (in my opinion) is the harder part of the tutorial, so please listen carefully
  You are going to be in the caracther select select screen and have to select the "The Hunter" with left mouse click button (If you follow the steps on how to open the game, you will know what that button is)
  
  
  
  
  
• Fourth Step
  Ok now the most important step, You are going to press the interact button (if you are on default controls, thats the "E" key on your keyboard to for you, but I dont know the buttons on controller) next to the dog! The following images are an exemple of it being done correctly
  
  
  
  
  (Note that after enough time, the dog will do an silly pose such as here!)
  

• Has a 5% chance to dig up a pickup upon completing a room.
  (A pickup is like a heart, key, some other useful stuff, etc)
  
  
• Identifies chest Mimics by barking.
  (Dog will not bark at Pedestal Mimics or Wall Mimics.)
  
  
• Is obtainable by other characthers, but The Hunter starts with it

• Cannot be dropped when playing as The Hunter.
  
  
• The dog cannot be interacted with if the player is currently in combat.
  
  
• If the player has flight, they can still interact with the dog but there will be no petting animation.
  
  
• If the player is playing as The Marine and they lose his helmet, he will have no more petting animation, but he'll still be able to interact with the Dog.
  
  
• Most Gungeoneers smile when petting the Dog, with the exception of The Robot, whose monitor displays a heart, and The Pilot and The Bullet, with both remaining serious during the animation. The reason is unknown.
  
  
• The Convict's petting animation is slower than the other characters. This doesn't happen when using her alternate costume.
  
  
• The Gunslinger will not smile while petting the dog as he is expressionless.
  
  
• The dog can dodge-roll across pits.
  
  
• If the player has Baby Good Mimic and it transforms into the dog, each individual Dog will have a chance to find an item, both will play the digging animation if one finds an item, and both can be pet if interacted with.
  
  
• The ability to pet the dog was added in the Farewell to Arms Update, in direct response to a post from twitter account @CanYouPetTheDog, calling out Enter the Gungeon for containing a non-pettable dog. According to Dodge Roll designer Dave Crooks, while the idea of making the dog pettable had come up before in development, it was the intervention of @CanYouPetTheDog that spurred the change.
  
  
• The Dog's name implies that the Hunter got him as a replacement for her Wolf, Junior.
  
  
• Also note that the two players in the game CAN pet the dog!

Here they are for those that found my guide and need more instructions on how
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1893505093&searchtext=How+to+pet+the+dog

https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=2039733029&searchtext=How+to+pet+the+dog

https://enterthegungeon.wiki.gg/wiki/Dog#References