The scene: an impromptu frozen yogurt date. The girl, unstoppably excited about her signature combination of pistachio yogurt, raspberries, and mochi, dives in a bit too quickly. The cold enters the roof of her mouth and envelopes her. She stops, mid conversation, the brain freeze apparent on her face.
The boy stares at her with a loving smile on his face. Through the girl's crushing pain, she appreciates this look, as if he wishes he could do anything to make it stop. When it does, the girl gives the boy a look of relief.
He opens his mouth, the girl can only assume, to tell her he can't stand to see her in such pain; that he hopes he never has to see that pained look on her face again.
The boy opens his mouth,
"Know why that hurts? The blood vessels in the roof of your mouth rapidly contract then expand, causing pain in that nerve, which then refers to the covering of your brain. The covering of your bain is literally what's hurting you right now. That's why they call it brain freeze."
The girl makes a mental note of the subtle difference between the boy's "loving" gaze and the boy's "I know something you don't know" gaze.