[ The look of pure boredom on his face speaks volumes: Shinpachi, he is not impressed. ]

Shinpattsu-san, I promise you, I'm not jealous of your muscles. I wouldn't wanna look like a walking bicep.

[ Even with the pat on the head, the most he does is wrinkle his nose.

...up until Shinpachi calls him a kid. ]

Nuh uh. Maybe it you'd stop eating my food I'd grow some more! Or maybe I'll just chew on you instead! [ And now he's going to make a grab for Shinpachi's arm, intent on doing exactly what he threatened. ]