The Question and Answer section for The Lottery and Other Stories is a great resource to ask questions, find answers, and discuss the novel.
This shows a sense of desperation and change in tone for both Tessie and the rising action of the story,
She hesitated for a minute, looking around defiantly and then set her lips and went up to the box. She snatched a paper out...
That would mean to talk without stopping: to go on and on monotonously.
This means that little Davie is encouraged to stone, murder, his own mother. This contributes to the twisted irony of the situation.