Hate to admit it. I don’t get the joke…
What do dogs do a lot?
Like barking?
The dog itches, and he has been given the collar so he cannot scratch. He hopes that the other dog will scratch him to relieve his itch. To me, the joke is that he has made an explicitly human or at least primatal request to resolve the situation–a dog would not be able to imagine the other dog’s need to scratch, and likely not even envision the obvious means of helping if it did.
There should have been balls on the dog. No balls, no joke.
That joke had no balls.
Frankly, I’m surprised he even made it to adulthood.
It depends on what’s in the paste. 
Ralph made it to adulthood and got cloned a bazillion times. You need more than paste to wipe out his DNA!
Really? Calling all dog psychologists!
I would not put that type of reasoning past them. On the contrary, I take the joke as being that while a hooman would be embarrassed to ask, a dog would not have the same concept of shame / privacy.
When you gotta work, you find a way
From a pal in Costa Rica. They have restrictions on traffic for private cars due to COVID, based on plate number. If your vehicle has no plate, though…
A real entrepreneur knows where to find opportunities!
