The scene where Jacob tells Liana he doesn't want to kiss her. Chapter 19 of the Little Things.
"Jacob? Why do grownups kiss?" A six year old Liana asked innocently, but with genuine curiosity.
The boy being questioned wrinkled his nose. "Mommy said people do it when they love each other."
The two youngsters were seated on the living room couch of the Black's house, looking at the wedding pictures of Jacob's parents. Liana's father had brought her and her older sister Bella, who was playing with Jacob's older twin sisters, over to visit as he went out fishing with Billy.
"It looks weird." Liana stated, looking flatly at the image of the newlywed couple kissing.
"Yeah. Might get girl germs." Jacob stuck out his tongue.
"Girls don't have germs!" She huffed. "Boys do!"
"Uh, no they don't." Jacob denied.
And so they went back and forth insisting that the other had germs. Eventually they stopped and stared at each other in silence.
"That's it!" Jacob shouted, making Liana jump.
"What?"
"Well, you say I have germs, and I say you have germs, and we both think the other is wrong. So if we kiss, and one of us get sick then we will know," Jacob declared triumphantly.
Liana looked aghast. "You want us to kiss?!"
Jacob wrinkled his nose. "I don't want to kiss you, but I want to know who's right."
"Fine," she sighed.
They looked at each other, screwed up their faces and scooted closer together. They leaned forward, and as fast as their lips touched they separated again. They quickly moved away again.
"Blech, how can grownups do that?!" Liana exclaimed, moving to wipe her mouth.
Jacob grabbed her arm. "Don't do that! You might wipe the boy germs away! And I'm never ever kissing anyone else again!"
"Me neither. Never ever," Liana repeated.
Soon the event was forgotten as neither of them got sick. They never spoke of it again and neither did Sarah Black, who had over heard the tail end of the conversation from the kitchen, though she found it most amusing.
And how true the statement turned out to be as the next person they kissed was each other, over ten years later. And after that, well, they had no interest in kissing anyone but each other.