Maybe the reason wild dogs were domesticated is because they needed someone to scratch inside their ears
mizzyc@kbin.social to 
It's deeply pleasuring to scratch inside your ears and of course dogs can't do it. Probably anyone would accept to be domesticated just to feel this pleasure too!
The inside of dog's ears are very delicate, you shouldn't scratch inside them.
Of course, that's a good reminder! But according to my dog's vet, it shouldn't be a problem if done cautious, not frequently, not going deep and with a gauze around your finger. She do it sometimes including to see if there's anything causing the itch by the color left on the gauze.
EDIT: I'm not a vet, so if I'm wrong, someone please correct me! Just saying this according to what my dog's vet said.