"What's That Hard Thing Rolling Back And Forth Across The Ball Joint In My Shoulder?"

"It's a muscle."

"OW. Is it supposed to do that?"

"Uh- No. It's supposed to be like that" (holds out hand, fingers splayed)"Yours is like that" (holds out hand with fingers scrinched together like an angry duck shadow puppet)

"Mmm. How can I, a person with no visible reflexes, get so tightly wound?!"

It's an oxymoron.