In "Robert's Divorce", during a flashback to one of Joanne's control-freak moments while she and Robert were still married, she used the exact phrase "crazy chin" when Robert touched a piece of popcorn to his chin before putting it in his mouth. In "Raybert", Natasha, Robert's girlfriend at the time, also acknowledged Robert's habit, but called it "the chin thing."
Amy says that Robert screams at pickles, even though in several other episodes Robert eats pickles.
Hank: (to Robert about his chin habit) Is that how you test the temperature of your food before you eat it?
Pat: Hank, that's silly. Then he would have a big red spot on his chin every time the food was too hot!
Peter: Every family has its odd ball. With us it's mom.
Frank: (about Robert's chin habit) Eh, he was doing it way before then, anyway. I remember this one time—
Robert: Oh, God. This is like the Special Psycho Edition of This is Your Life!
Debra: Hey, can I ask you something? I mean, forgive me, Robert, but why do you do the chin thing?
Robert: Um... have you not been following?
Debra: Oh, no, I understand the whole stress thing, but of all the ways you can deal with stress....you know, grinding your teeth, biting your nails—
Frank: Pulling your hair out!
Debra: Why do you do that particular thing? Why do you touch food to your chin?
Robert: Because the voices tell me to. There, you happy now?
Robert: (to Amy) Oh, and all those things I said last night, they aren't true. You have the cutest walk I've ever seen, and you don't eat like a beaver! (they cry and hug)
Debra: What happened over there last night?
Debra: (after Ray tells a story about when he first saw Robert do the chin thing) Robert, maybe you were so afraid of being caught by Marie that you.....forgot how to eat?
Ray: (sarcastically) Really? That's what you learned in college? What, was it one of those hair colleges?
Ray: Listen, Ma, it's normal for couples to fight, okay? Remember that in case you and Dad ever have one.
Robert: I love you.
Amy: I love you. (they hug)
Frank: I love you, too. Bye now!
Frank: (about Robert) He is not moving back here! I finally had the both of you kids out of the house. I only had one left to go.
Amy: Are you stressed? Cause it's okay if you're stressed I just want to know if you're stressed. Are you stressed?
Robert: Maybe a little bit now.
Frank: (about Robert) I took him to the lodge, and he was eyeing this jar of pickles. So I give him one, and he starts doing his chin thing, so the guys gave him more pickles so he's keep doing it. Turns out those pickles were on that counter when the lodge first opened in 1952. Robert threw up like Niagara Falls! (starts laughing hysterically, turns to Amy) Ah, well, does that answer your question?
Amy: No, but now I know why Robert screams at pickles.
(Ray tells a story about how Robert and him almost got away with eating candy)
Ray: But guess what was stuck to Robert's chin? The tail of a marshmallow duck!
Marie: And what did I do to make sure it didn't happen again?
Ray and Robert: You gave our candy to poor children.
Frank: It was delicious!
(trying to help solve Robert's chin problem)
Amy: So you don't think I should do anything?
Debra: Well, I don't know if you can cure him, but anything you can do to help relieve some of the stress....I'm sure it can't hurt.
Ray: Why don't you get one of those funnels that dogs wear around their neck, and just throw the food in there?