Ah. Ear cleaning.
 
There are spots in your ears canals that, if carefully scratched, can make you feel really good. They feel like scratching an itch but it can last even minutes. I’m not joking. Every human has these spots but their locations vary, so if you go finding yours be VERY careful; you don’t want to poke holes in your eardrum. You need something thinner than your finger to reach the deepest spots. Paperclips work fine and so does thin metal wire if you bend it so the end is dull (works also for removing earwax).
 
Now imagine gently scratching ponies’ ears.

pony ear cleaning!