They made him think of something that Aunt Susan had told him.

She said that if he counted seven stars for seven nights, at the same time repeating a charm which she taught him, and making a wish, he'd certainly get what he wanted at the end of the week.
Now he stopped still in the path, and slowly pointing to each star with his little black forefinger, as he counted them, solemnly repeated the charm: "Star-light, star bright, Seventh star I've seen to-night; I wish I may and I wish I might Have the wish come true I wish to-night." "Come on in, chile! What you gawkin' at ?" called Mammy from the doorway.
John Jay made no answer.

It would have broken the charm to have spoken again before going to sleep.

He hurried into the house, glad that Mammy was so occupied with her company that she could pay no attention to him.
She stood in the door with them so long that John Jay was in bed by the time she came in.

Although he pretended to be asleep, inwardly he was in a quiver of excitement.
"I'll count 'em every night," he thought.