Storyboard 18
1) JEFF: She's not my girlfriend.
2) MABLE: Stop acting like a baby, Jeff
JEFF: I'm not acting like a baby!
3) MABLE: Right. I forgot. "I'm not acting like a baby, Mommy, I don't feel good and now I'm going to mope."
4) JEFF: I'm not moping. And I really don't feel good.
Jeff's putting his feet up on the dashboard in the last panel--it's what I do when I feel like being a brat. It's really a bad idea, of course, cause if the airbag goes off it'll hurt you. But still.