Ear Wank
Ear wanking is when you stick your finger up your own ear and yank it like you're trying to pull out the ear wax and your brain. It feels good, like when you scratch a bad itch, but way more satisfying and way less gross.
My mom caught me ear wanking during math class and I had to explain why I was doing it.
I ear wanked so hard during lunch that I got a stomachache and a compliment from the principal.
I was ear wanking in the bathroom when my friend walked in and I had to pretend I was checking my hair.